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Ebrahimie E, Rahimirad S, Tahsili M, Mohammadi-Dehcheshmeh M. Alternative RNA splicing in stem cells and cancer stem cells: Importance of transcript-based expression analysis. World J Stem Cells 2021; 13:1394-1416. [PMID: 34786151 PMCID: PMC8567453 DOI: 10.4252/wjsc.v13.i10.1394] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/21/2021] [Accepted: 09/14/2021] [Indexed: 02/06/2023] Open
Abstract
Alternative ribonucleic acid (RNA) splicing can lead to the assembly of different protein isoforms with distinctive functions. The outcome of alternative splicing (AS) can result in a complete loss of function or the acquisition of new functions. There is a gap in knowledge of abnormal RNA splice variants promoting cancer stem cells (CSCs), and their prospective contribution in cancer progression. AS directly regulates the self-renewal features of stem cells (SCs) and stem-like cancer cells. Notably, octamer-binding transcription factor 4A spliced variant of octamer-binding transcription factor 4 contributes to maintaining stemness properties in both SCs and CSCs. The epithelial to mesenchymal transition pathway regulates the AS events in CSCs to maintain stemness. The alternative spliced variants of CSCs markers, including cluster of differentiation 44, aldehyde dehydrogenase, and doublecortin-like kinase, α6β1 integrin, have pivotal roles in increasing self-renewal properties and maintaining the pluripotency of CSCs. Various splicing analysis tools are considered in this study. LeafCutter software can be considered as the best tool for differential splicing analysis and identification of the type of splicing events. Additionally, LeafCutter can be used for efficient mapping splicing quantitative trait loci. Altogether, the accumulating evidence re-enforces the fact that gene and protein expression need to be investigated in parallel with alternative splice variants.
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Affiliation(s)
- Esmaeil Ebrahimie
- School of Animal and Veterinary Sciences, The University of Adelaide, Adelaide 5005, South Australia, Australia
- La Trobe Genomics Research Platform, School of Life Sciences, College of Science, Health and Engineering, La Trobe University, Melbourne 3086, Australia
- School of Biosciences, The University of Melbourne, Melbourne 3010, Australia,
| | - Samira Rahimirad
- Department of Medical Genetics, National Institute of Genetic Engineering and Biotechnology, Tehran 1497716316, Iran
- Division of Urology, Department of Surgery, McGill University and the Research Institute of the McGill University Health Centre, Montreal H4A 3J1, Quebec, Canada
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Wang J, Wang C, Li L, Yang L, Wang S, Ning X, Gao S, Ren L, Chaulagain A, Tang J, Wang T. Alternative splicing: An important regulatory mechanism in colorectal carcinoma. Mol Carcinog 2021; 60:279-293. [PMID: 33629774 DOI: 10.1002/mc.23291] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 02/01/2021] [Accepted: 02/11/2021] [Indexed: 12/17/2022]
Abstract
Alternative splicing (AS) is a process that produces various mRNA splicing isoforms via different splicing patterns of mRNA precursors (pre-mRNAs). AS is the primary mechanism for increasing the types and quantities of proteins to improve biodiversity and influence multiple biological processes, including chromatin modification, signal transduction, and protein expression. It has been reported that AS is involved in the tumorigenesis and development of colorectal carcinoma (CRC). In this review, we delineate the concept, types, regulatory processes, and technical advances of AS and focus on the role of AS in CRC initiation, progression, treatment, and prognosis. This summary of the current knowledge about AS will contribute to our understanding of CRC initiation and development. This study will help in the discovery of novel biomarkers and therapeutic targets for CRC prognosis and treatment.
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Affiliation(s)
- Jianyi Wang
- Department of Pathology, Harbin Medical University, Harbin, China
| | - Chuhan Wang
- Department of Pathology, Harbin Medical University, Harbin, China
| | - Le Li
- Department of Pathology, Harbin Medical University, Harbin, China
| | - Lirui Yang
- Department of Pathology, Harbin Medical University, Harbin, China
| | - Shuoshuo Wang
- Department of Pathology, Harbin Medical University, Harbin, China
| | - Xuelian Ning
- Department of Pathology, Harbin Medical University, Harbin, China
| | - Shuangshu Gao
- Department of Pathology, Harbin Medical University, Harbin, China
| | - Lili Ren
- Department of Pathology, Harbin Medical University, Harbin, China
| | - Anita Chaulagain
- Department of Microbiology, Harbin Medical University, Harbin, China
| | - Jing Tang
- Department of Pathology, Harbin Medical University, Harbin, China.,Department of Bioinformatics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Tianzhen Wang
- Department of Pathology, Harbin Medical University, Harbin, China
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Chae S, Kim JS, Jun KM, Lee SB, Kim MS, Nahm BH, Kim YK. Analysis of Genes with Alternatively Spliced Transcripts in the Leaf, Root, Panicle and Seed of Rice Using a Long Oligomer Microarray and RNA-Seq. Mol Cells 2017; 40:714-730. [PMID: 29047256 PMCID: PMC5682249 DOI: 10.14348/molcells.2017.2297] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 08/21/2017] [Accepted: 08/24/2017] [Indexed: 11/30/2022] Open
Abstract
Pre-mRNA splicing further increases protein diversity acquired through evolution. The underlying driving forces for this phenomenon are unknown, especially in terms of gene expression. A rice alternatively spliced transcript detection microarray (ASDM) and RNA sequencing (RNA-Seq) were applied to differentiate the transcriptome of 4 representative organs of Oryza sativa L. cv. Ilmi: leaves, roots, 1-cm-stage panicles and young seeds at 21 days after pollination. Comparison of data obtained by microarray and RNA-Seq showed a bell-shaped distribution and a co-lineation for highly expressed genes. Transcripts were classified according to the degree of organ enrichment using a coefficient value (CV, the ratio of the standard deviation to the mean values): highly variable (CVI), variable (CVII), and constitutive (CVIII) groups. A higher index of the portion of loci with alternatively spliced transcripts in a group (IAST) value was observed for the constitutive group. Genes of the highly variable group showed the characteristics of the examined organs, and alternatively spliced transcripts tended to exhibit the same organ specificity or less organ preferences, with avoidance of 'organ distinctness'. In addition, within a locus, a tendency of higher expression was found for transcripts with a longer coding sequence (CDS), and a spliced intron was the most commonly found type of alternative splicing for an extended CDS. Thus, pre-mRNA splicing might have evolved to retain maximum functionality in terms of organ preference and multiplicity.
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Affiliation(s)
- Songhwa Chae
- Division of Bioscience and Bioinformatics, Myongji University, Yongin 17058,
Korea
| | - Joung Sug Kim
- Division of Bioscience and Bioinformatics, Myongji University, Yongin 17058,
Korea
| | - Kyong Mi Jun
- GreenGene Biotech Inc., 116, Yongin 17058,
Korea
| | - Sang-Bok Lee
- Central Area Crop Breeding Research Division, National Institute of Crop Science, Chuncheon 24219,
Korea
| | | | - Baek Hie Nahm
- Division of Bioscience and Bioinformatics, Myongji University, Yongin 17058,
Korea
- GreenGene Biotech Inc., 116, Yongin 17058,
Korea
| | - Yeon-Ki Kim
- Division of Bioscience and Bioinformatics, Myongji University, Yongin 17058,
Korea
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Novel transcription factor variants through RNA-sequencing: the importance of being "alternative". Int J Mol Sci 2015; 16:1755-71. [PMID: 25590302 PMCID: PMC4307332 DOI: 10.3390/ijms16011755] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 12/26/2014] [Indexed: 12/22/2022] Open
Abstract
Alternative splicing is a pervasive mechanism of RNA maturation in higher eukaryotes, which increases proteomic diversity and biological complexity. It has a key regulatory role in several physiological and pathological states. The diffusion of Next Generation Sequencing, particularly of RNA-Sequencing, has exponentially empowered the identification of novel transcripts revealing that more than 95% of human genes undergo alternative splicing. The highest rate of alternative splicing occurs in transcription factors encoding genes, mostly in Krüppel-associated box domains of zinc finger proteins. Since these molecules are responsible for gene expression, alternative splicing is a crucial mechanism to "regulate the regulators". Indeed, different transcription factors isoforms may have different or even opposite functions. In this work, through a targeted re-analysis of our previously published RNA-Sequencing datasets, we identified nine novel transcripts in seven transcription factors genes. In silico analysis, combined with RT-PCR, cloning and Sanger sequencing, allowed us to experimentally validate these new variants. Through computational approaches we also predicted their novel structural and functional properties. Our findings indicate that alternative splicing is a major determinant of transcription factor diversity, confirming that accurate analysis of RNA-Sequencing data can reliably lead to the identification of novel transcripts, with potentially new functions.
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TIPMaP: a web server to establish transcript isoform profiles from reliable microarray probes. BMC Genomics 2013; 14:922. [PMID: 24373374 PMCID: PMC3884118 DOI: 10.1186/1471-2164-14-922] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Accepted: 12/23/2013] [Indexed: 01/22/2023] Open
Abstract
Background Standard 3′ Affymetrix gene expression arrays have contributed a significantly higher volume of existing gene expression data than other microarray platforms. These arrays were designed to identify differentially expressed genes, but not their alternatively spliced transcript forms. No resource can currently identify expression pattern of specific mRNA forms using these microarray data, even though it is possible to do this. Results We report a web server for expression profiling of alternatively spliced transcripts using microarray data sets from 31 standard 3′ Affymetrix arrays for human, mouse and rat species. The tool has been experimentally validated for mRNAs transcribed or not-detected in a human disease condition (non-obstructive azoospermia, a male infertility condition). About 4000 gene expression datasets were downloaded from a public repository. ‘Good probes’ with complete coverage and identity to latest reference transcript sequences were first identified. Using them, ‘Transcript specific probe-clusters’ were derived for each platform and used to identify expression status of possible transcripts. The web server can lead the user to datasets corresponding to specific tissues, conditions via identifiers of the microarray studies or hybridizations, keywords, official gene symbols or reference transcript identifiers. It can identify, in the tissues and conditions of interest, about 40% of known transcripts as ‘transcribed’, ‘not-detected’ or ‘differentially regulated’. Corresponding additional information for probes, genes, transcripts and proteins can be viewed too. We identified the expression of transcripts in a specific clinical condition and validated a few of these transcripts by experiments (using reverse transcription followed by polymerase chain reaction). The experimental observations indicated higher agreements with the web server results, than contradictions. The tool is accessible at http://resource.ibab.ac.in/TIPMaP. Conclusion The newly developed online tool forms a reliable means for identification of alternatively spliced transcript-isoforms that may be differentially expressed in various tissues, cell types or physiological conditions. Thus, by making better use of existing data, TIPMaP avoids the dependence on precious tissue-samples, in experiments with a goal to establish expression profiles of alternative splice forms – at least in some cases.
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Roy B, Haupt LM, Griffiths LR. Review: Alternative Splicing (AS) of Genes As An Approach for Generating Protein Complexity. Curr Genomics 2013; 14:182-94. [PMID: 24179441 PMCID: PMC3664468 DOI: 10.2174/1389202911314030004] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 02/08/2013] [Accepted: 02/25/2013] [Indexed: 12/22/2022] Open
Abstract
Prior to the completion of the human genome project, the human genome was thought to have a greater number of genes as it seemed structurally and functionally more complex than other simpler organisms. This along with the belief of “one gene, one protein”, were demonstrated to be incorrect. The inequality in the ratio of gene to protein formation gave rise to the theory of alternative splicing (AS). AS is a mechanism by which one gene gives rise to multiple protein products. Numerous databases and online bioinformatic tools are available for the detection and analysis of AS. Bioinformatics provides an important approach to study mRNA and protein diversity by various tools such as expressed sequence tag (EST) sequences obtained from completely processed mRNA. Microarrays and deep sequencing approaches also aid in the detection of splicing events. Initially it was postulated that AS occurred only in about 5% of all genes but was later found to be more abundant. Using bioinformatic approaches, the level of AS in human genes was found to be fairly high with 35-59% of genes having at least one AS form. Our ability to determine and predict AS is important as disorders in splicing patterns may lead to abnormal splice variants resulting in genetic diseases. In addition, the diversity of proteins produced by AS poses a challenge for successful drug discovery and therefore a greater understanding of AS would be beneficial.
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Affiliation(s)
- Bishakha Roy
- Genomics Research Centre, Griffith Health Institute, Griffith University Gold Coast, Queensland 4222, Australia
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Al Saleh S, Al Mulla F, Luqmani YA. Estrogen receptor silencing induces epithelial to mesenchymal transition in human breast cancer cells. PLoS One 2011; 6:e20610. [PMID: 21713035 PMCID: PMC3119661 DOI: 10.1371/journal.pone.0020610] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Accepted: 05/05/2011] [Indexed: 12/15/2022] Open
Abstract
We propose the hypothesis that loss of estrogen receptor function which leads to endocrine resistance in breast cancer, also results in trans-differentiation from an epithelial to a mesenchymal phenotype that is responsible for increased aggressiveness and metastatic propensity. siRNA mediated silencing of the estrogen receptor in MCF7 breast cancer cells resulted in estrogen/tamoxifen resistant cells (pII) with altered morphology, increased motility with rearrangement and switch from a keratin/actin to a vimentin based cytoskeleton, and ability to invade simulated components of the extracellular matrix. Phenotypic profiling using an Affymetrix Human Genome U133 plus 2.0 GeneChip indicated geometric fold changes ≥ 3 in approximately 2500 identifiable unique sequences, with about 1270 of these being up-regulated in pII cells. Changes were associated with genes whose products are involved in cell motility, loss of cellular adhesion and interaction with the extracellular matrix. Selective analysis of the data also showed a shift from luminal to basal cell markers and increased expression of a wide spectrum of genes normally associated with mesenchymal characteristics, with consequent loss of epithelial specific markers. Over-expression of several peptide growth factors and their receptors are indicative of an increased contribution to the higher proliferative rates of pII cells as well as aiding their potential for metastatic activity. Signalling molecules that have been identified as key transcriptional drivers of epithelial to mesenchymal transition were also found to be elevated in pII cells. These data support our hypothesis that induced loss of estrogen receptor in previously estrogen/antiestrogen sensitive cells is a trigger for the concomitant loss of endocrine dependence and onset of a series of possibly parallel events that changes the cell from an epithelial to a mesenchymal type. Inhibition of this transition through targeting of specific mediators may offer a useful supplementary strategy to circumvent the effects of loss of endocrine sensitivity.
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Affiliation(s)
- Sanaa Al Saleh
- Faculty of Pharmacy, Kuwait University, Safat, Kuwait
- College of Graduate Studies, Kuwait University, Safat, Kuwait
| | - Fahd Al Mulla
- Faculty of Medicine, Kuwait University, Safat, Kuwait
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Plant N. Expressed sequence tags (ESTs) and single nucleotide polymorphisms (SNPs): What large-scale sequencing projects can tell us about ADME. Xenobiotica 2009; 36:860-76. [PMID: 17118912 DOI: 10.1080/00498250600861603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
To date over 800 complete genomes have been sequenced, with many more partially complete. Coupled with the large amount of mRNA transcript sequence data being produced from expression studies, there is now a daunting amount of information available to the research scientist. This review examines how this information may be best used, focusing on examples from sequences encoding absorption, distribution, metabolism and excretion (ADME)-related proteins in particular. Through the use of phylogenetic, splice variant and single nucleotide polymorphism (SNP) analysis, the review examines not only how insights into species-specific responses to drug exposure may be gained, but also how best to utilize this information to predict both individual human responses and the impact of population variance in response.
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Affiliation(s)
- N Plant
- School of Biomedical and Molecular Sciences, University of Surrey, Guildford, UK.
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AspAlt: A tool for inter-database, inter-genomic and user-specific comparative analysis of alternative transcription and alternative splicing in 46 eukaryotes. Genomics 2009; 94:48-54. [DOI: 10.1016/j.ygeno.2009.02.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Revised: 12/16/2008] [Accepted: 02/21/2009] [Indexed: 12/22/2022]
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Gu L, Guo R. Genome-wide detection and analysis of alternative splicing for nucleotide binding site-leucine-rich repeats sequences in rice. J Genet Genomics 2009; 34:247-57. [PMID: 17498622 DOI: 10.1016/s1673-8527(07)60026-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2006] [Accepted: 08/03/2006] [Indexed: 11/20/2022]
Abstract
Alternative splicing is a major contributor to genomic complexity and proteome diversity, yet the analysis of alternative splicing for the sequence containing nucleotide binding site and leucine-rich repeats (NBS-LRR) domain has not been explored in rice (Oryza sativa L.). Hidden Markov model (HMM) searches were performed for NBS-LRR domain. 875 NBS-LRR-encoding sequences were obtained from the Institute for Genomic Research (TIGR). All of them were used to blast Knowledge-based Oryza Molecular Biological Encyclopaedia (KOME), TIGR rice gene index (TGI), and Universal Protein Resource (UniProt) to obtain homologous full-length cDNAs (FL-cDNAs), tentative consensus sequences, and protein sequences. Alternative splicing events were detected from genomic alignment of FL-cDNAs, tentative consensus sequences, and protein sequences, which provide valuable information on splice variants of genes. These sequences were aligned to the corresponding BAC sequences using the Spidey and Sim4 programs and each of the proteins was aligned by tBLASTn. Of the 875 NBS-LRR sequences, 119 (13.6%) sequences had alternative splicing where multiple FL-cDNAs, TGI sequences and proteins corresponded to the same gene. 71 intron retention events, 20 exon skipping events, 16 alternative termination events, 25 alternative initiation events, 12 alternative 5' splicing events, and 16 alternative 3' splicing events were identified. Most of these alternative splices were supported by two or more transcripts. The data sets are available at http://www.bioinfor.org Furthermore, the bioinformatics analysis of splice boundaries showed that exon skipping and intron retention did not exhibit strong consensus. This implies a different regulation mechanism that guides the expression of splice isoforms. This article also presents the analysis of the effects of intron retention on proteins. The C-terminal regions of alternative proteins turned out to be more variable than the N-terminal regions. Finally, tissue distribution and protein localization of alternative splicing were explored. The largest categories of tissue distributions for alternative splicing were shoot and callus. More than one-thirds of protein localization for splice forms was plasma membrane and cytoplasm. All the NBS-LRR proteins for splice forms may have important function in disease resistance and activate downstream signaling pathways.
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Affiliation(s)
- Lianfeng Gu
- College of Agriculture, Guangdong Ocean University, Zhanjiang 524088, China
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11
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A general definition and nomenclature for alternative splicing events. PLoS Comput Biol 2008; 4:e1000147. [PMID: 18688268 PMCID: PMC2467475 DOI: 10.1371/journal.pcbi.1000147] [Citation(s) in RCA: 175] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2007] [Accepted: 07/01/2008] [Indexed: 11/19/2022] Open
Abstract
Understanding the molecular mechanisms responsible for the regulation of the transcriptome present in eukaryotic cells is one of the most challenging tasks in the postgenomic era. In this regard, alternative splicing (AS) is a key phenomenon contributing to the production of different mature transcripts from the same primary RNA sequence. As a plethora of different transcript forms is available in databases, a first step to uncover the biology that drives AS is to identify the different types of reflected splicing variation. In this work, we present a general definition of the AS event along with a notation system that involves the relative positions of the splice sites. This nomenclature univocally and dynamically assigns a specific “AS code” to every possible pattern of splicing variation. On the basis of this definition and the corresponding codes, we have developed a computational tool (AStalavista) that automatically characterizes the complete landscape of AS events in a given transcript annotation of a genome, thus providing a platform to investigate the transcriptome diversity across genes, chromosomes, and species. Our analysis reveals that a substantial part—in human more than a quarter—of the observed splicing variations are ignored in common classification pipelines. We have used AStalavista to investigate and to compare the AS landscape of different reference annotation sets in human and in other metazoan species and found that proportions of AS events change substantially depending on the annotation protocol, species-specific attributes, and coding constraints acting on the transcripts. The AStalavista system therefore provides a general framework to conduct specific studies investigating the occurrence, impact, and regulation of AS. The genome sequence is said to be an organism's blueprint, a set of instructions driving the organism's biology. The unfolding of these instructions—the so-called genes—is initiated by the transcription of DNA into RNA molecules, which subsequently are processed before they can take their functional role. During this processing step, initially identical RNA molecules may result in different products through a process known as alternative splicing (AS). AS therefore allows for widening the diversity from the limited repertoire of genes, and it is often postulated as an explanation for the apparent paradox that complex and simple organisms resemble in their number of genes; it characterizes species, individuals, and developmental and cellular conditions. Comparing the differences of AS products between cells may help to reveal the broad molecular basis underlying phenotypic differences—for instance, between a cancer and a normal cell. An obstacle for such comparisons has been that, so far, no paradigm existed to delineate each single quantum of AS, so-called AS events. Here, we describe a possibility of exhaustively decomposing AS complements into qualitatively different groups of events and a nomenclature to unequivocally denote them. This typological catalogue of AS events along with their observed frequencies represent the AS landscape, and we propose a procedure to automatically identify such landscapes. We use it to describe the human AS landscape and to investigate how it has changed throughout evolution.
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Castrignanò T, D’Antonio M, Anselmo A, Carrabino D, D’Onorio De Meo A, D’Erchia AM, Licciulli F, Mangiulli M, Mignone F, Pavesi G, Picardi E, Riva A, Rizzi R, Bonizzoni P, Pesole G. ASPicDB: A database resource for alternative splicing analysis. Bioinformatics 2008; 24:1300-4. [DOI: 10.1093/bioinformatics/btn113] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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Abstract
In recent years, genome-wide detection of alternative splicing based on Expressed Sequence Tag (EST) sequence alignments with mRNA and genomic sequences has dramatically expanded our understanding of the role of alternative splicing in functional regulation. This chapter reviews the data, methodology, and technical challenges of these genome-wide analyses of alternative splicing, and briefly surveys some of the uses to which such alternative splicing databases have been put. For example, with proper alternative splicing database schema design, it is possible to query genome-wide for alternative splicing patterns that are specific to particular tissues, disease states (e.g., cancer), gender, or developmental stages. EST alignments can be used to estimate exon inclusion or exclusion level of alternatively spliced exons and evolutionary changes for various species can be inferred from exon inclusion level. Such databases can also help automate design of probes for RT-PCR and microarrays, enabling high throughput experimental measurement of alternative splicing.
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A new advance in alternative splicing databases: from catalogue to detailed analysis of regulation of expression and function of human alternative splicing variants. BMC Bioinformatics 2007; 8:180. [PMID: 17547750 PMCID: PMC1904244 DOI: 10.1186/1471-2105-8-180] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2006] [Accepted: 06/04/2007] [Indexed: 11/25/2022] Open
Abstract
Background Most human genes produce several transcripts with different exon contents by using alternative promoters, alternative polyadenylation sites and alternative splice sites. Much effort has been devoted to describing known gene transcripts through the development of numerous databases. Nevertheless, owing to the diversity of the transcriptome, there is a need for interactive databases that provide information about the potential function of each splicing variant, as well as its expression pattern. Description After setting up a database in which human and mouse splicing variants were compiled, we developed tools (1) to predict the production of protein isoforms from these transcripts, taking account of the presence of open reading frames and mechanisms that could potentially eliminate transcripts and/or inhibit their translation, i.e. nonsense-mediated mRNA decay and microRNAs; (2) to support studies of the regulation of transcript expression at multiple levels, including transcription and splicing, particularly in terms of tissue specificity; and (3) to assist in experimental analysis of the expression of splicing variants. Importantly, analyses of all features from transcript metabolism to functional protein domains were integrated in a highly interactive, user-friendly web interface that allows the functional and regulatory features of gene transcripts to be assessed rapidly and accurately. Conclusion In addition to identifying the transcripts produced by human and mouse genes, fast DB provides tools for analyzing the putative functions of these transcripts and the regulation of their expression. Therefore, fast DB has achieved an advance in alternative splicing databases by providing resources for the functional interpretation of splicing variants for the human and mouse genomes. Because gene expression studies are increasingly employed in clinical analyses, our web interface has been designed to be as user-friendly as possible and to be readily searchable and intelligible at a glance by the whole biomedical community.
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Lal A, Radhakrishnan S, Srinivas SS, Najarian K, Mays LE. Splice site detection using pruned maximum likelihood model. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2004:2836-9. [PMID: 17270868 DOI: 10.1109/iembs.2004.1403809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
In this paper we propose a novel method for splice site prediction using the maximum likelihood model. We performed maximum likelihood over the acceptor and donor datasets, and calculated sensitivity to measure the prediction performance. Then, by aggressive pruning of less informative nucleotide sites, while maintaining the high sensitivity of the method, we improved the model's performance in terms of the computational speed. In addition, after pruning fewer nucleotide sites need to be tagged, which in turn simplifies the development of an assay. The proposed method was tested on the human splice dataset. The results indicate that the proposed method was successful at splice site prediction with optimal sensitivity.
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Affiliation(s)
- Anuradha Lal
- Coll. of Inf. Technol., North Carolina Univ., Charlotte, NC, USA
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Noh SJ, Lee K, Paik H, Hur CG. TISA: tissue-specific alternative splicing in human and mouse genes. DNA Res 2006; 13:229-43. [PMID: 17107969 DOI: 10.1093/dnares/dsl011] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Alternative splicing (AS) is a mechanism by which multiple transcripts are produced from a single gene and is thought to be an important mechanism for tissue-specific expression of transcript isoforms. Here, we report a novel graphing method for transcript reconstruction and statistical prediction of tissue-specific AS. We applied three selection steps to generate the splice graph and predict the transcript isoforms: (i) a custom scoring rule for exon/intron sets, (ii) binomial statistics for selecting valid alternative splicing with a frequency of at least 1% for the predominant form and (iii) evaluation of transcript structure. We obtained 97 286 and 66 022 valid transcripts from 26 143 human and 27 741 mouse genes, respectively. In addition, we discovered 33 481 AS events for nine types of AS patterns in human. The statistical significance of tissue specificity for each gene, transcript and AS event was assessed based on EST tissue information, followed by a multiple testing correction procedure. In human, 12 711 genes, 16 016 transcripts and 1035 AS events were predicted to be tissue-specific (false discovery rate <0.01). This information on genes, transcript structures, AS events and their tissue specificities in human and mouse are freely accessible on the TISA website (http://tisa.kribb.re.kr/AGC/).
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Affiliation(s)
- Seung-Jae Noh
- Bioinformatics Lab. Plant genomics center KRIBB, 52 Eoeun-dong, Yuseong-gu, Daejon, 305-333 Korea
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Le Texier V, Riethoven JJ, Kumanduri V, Gopalakrishnan C, Lopez F, Gautheret D, Thanaraj TA. AltTrans: transcript pattern variants annotated for both alternative splicing and alternative polyadenylation. BMC Bioinformatics 2006; 7:169. [PMID: 16556303 PMCID: PMC1435940 DOI: 10.1186/1471-2105-7-169] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Accepted: 03/23/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The three major mechanisms that regulate transcript formation involve the selection of alternative sites for transcription start (TS), splicing, and polyadenylation. Currently there are efforts that collect data & annotation individually for each of these variants. It is important to take an integrated view of these data sets and to derive a data set of alternate transcripts along with consolidated annotation. We have been developing in the past computational pipelines that generate value-added data at genome-scale on individual variant types; these include AltSplice on splicing and AltPAS on polyadenylation. We now extend these pipelines and integrate the resultant data sets to facilitate an integrated view of the contributions from splicing and polyadenylation in the formation of transcript variants. DESCRIPTION The AltSplice pipeline examines gene-transcript alignments and delineates alternative splice events and splice patterns; this pipeline is extended as AltTrans to delineate isoform transcript patterns for each of which both introns/exons and 'terminating' polyA site are delineated; EST/mRNA sequences that qualify the transcript pattern confirm both the underlying splicing and polyadenylation. The AltPAS pipeline examines gene-transcript alignments and delineates all potential polyA sites irrespective of underlying splicing patterns. Resultant polyA sites from both AltTrans and AltPAS are merged. The generated database reports data on alternative splicing, alternative polyadenylation and the resultant alternate transcript patterns; the basal data is annotated for various biological features. The data (named as integrated AltTrans data) generated for both the organisms of human and mouse is made available through the Alternate Transcript Diversity web site at http://www.ebi.ac.uk/atd/. CONCLUSION The reported data set presents alternate transcript patterns that are annotated for both alternative splicing and alternative polyadenylation. Results based on current transcriptome data indicate that the contribution of alternative splicing is larger than that of alternative polyadenylation.
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Affiliation(s)
- Vincent Le Texier
- European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Jean-Jack Riethoven
- European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
- 18 Crispin Close, Haverhill, Suffolk, CB9 9PT, UK
| | - Vasudev Kumanduri
- European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Chellappa Gopalakrishnan
- European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Fabrice Lopez
- INSERM ERM206, Université de la Méditerranée, Luminy case 928 – 13 288 Marseille Cedex 09, France
| | - Daniel Gautheret
- INSERM ERM206, Université de la Méditerranée, Luminy case 928 – 13 288 Marseille Cedex 09, France
| | - Thangavel Alphonse Thanaraj
- European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
- 4 Copperfields, Saffron Walden, Essex, CB11 4FG, UK
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18
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de la Grange P, Dutertre M, Martin N, Auboeuf D. FAST DB: a website resource for the study of the expression regulation of human gene products. Nucleic Acids Res 2005; 33:4276-84. [PMID: 16052034 PMCID: PMC1181862 DOI: 10.1093/nar/gki738] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Human genes use various mechanisms to generate different transcripts having different exon content, which in turn generate multiple protein isoforms having differential and even opposite biological activities. To understand the biological consequences of gene transcriptional activity modulation, it is necessary to integrate the capability of genes to generate distinct functional products, particularly because transcriptional stimuli also affect the exon content of their target gene products. For this purpose, we have developed a bioinformatics suite, FAST DB, which defines easily and accurately the exon content of all known transcripts produced by human genes. In addition, several tools have been developed, including a graphical presentation of all gene products, a sequence multi-alignment of all gene transcripts and an in silico PCR computer program. The FAST DB interface also offers extensive links to website resources for promoter analysis and transcription factor binding site prediction, splicing regulatory sequence prediction, as well as 5′- and 3′-untranslated region analysis. FAST DB has been designed to facilitate studies that integrate transcriptional and post-transcriptional events to investigate the expression regulation of human gene products.
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Affiliation(s)
| | | | | | - Didier Auboeuf
- To whom correspondence should be addressed. Tel: +33 1 53 72 21 30; Fax: +33 1 42 40 95 57;
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19
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McCullough RM, Cantor CR, Ding C. High-throughput alternative splicing quantification by primer extension and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Nucleic Acids Res 2005; 33:e99. [PMID: 15967806 PMCID: PMC1153715 DOI: 10.1093/nar/gni098] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2005] [Revised: 05/20/2005] [Accepted: 06/02/2005] [Indexed: 11/25/2022] Open
Abstract
Alternative splicing is a significant contributor to transcriptome diversity, and a high-throughput experimental method to quantitatively assess predictions from expressed sequence tag and microarray analyses may help to answer questions about the extent and functional significance of these variants. Here, we describe a method for high-throughput analysis of known or suspected alternative splicing variants (ASVs) using PCR, primer extension and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Reverse-transcribed mRNA is PCR amplified with primers surrounding the site of alternative splicing, followed by a primer extension reaction designed to target sequence disparities between two or more variants. These primer extension products are assayed on a MALDI-TOF mass spectrometer and analyzed automatically. This method is high-throughput, highly accurate and reproducible, allowing for the verification of the existence of splicing variants in a variety of samples. An example given also demonstrates how this method can eliminate potential pitfalls from ordinary gel electrophoretic analysis of splicing variants where heteroduplexes formed from different variants can produce erroneous results. The new method can be used to create alternative variant profiles for cancer markers, to study complex splicing regulation, or to screen potential splicing therapies.
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Affiliation(s)
- Ron M. McCullough
- Program of Molecular and Cellular Biology and BiochemistryBoston, MA 02215, USA
- Center for Advanced Biotechnology36 Cummington Street, Boston, MA 02215, USA
- Centre for Emerging Infectious Diseases, 2/F, School of Public Health, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, New Territories, Hong Kong Special Administrative Region
| | - Charles R. Cantor
- Center for Advanced Biotechnology36 Cummington Street, Boston, MA 02215, USA
| | - Chunming Ding
- Centre for Emerging Infectious Diseases, 2/F, School of Public Health, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, New Territories, Hong Kong Special Administrative Region
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20
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Huang HD, Horng JT, Lin FM, Chang YC, Huang CC. SpliceInfo: an information repository for mRNA alternative splicing in human genome. Nucleic Acids Res 2005; 33:D80-5. [PMID: 15608290 PMCID: PMC540083 DOI: 10.1093/nar/gki129] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We have developed an information repository named SpliceInfo to collect the occurrences of the four major alternative-splicing (AS) modes in human genome; these include exon skipping, 5′-alternative splicing, 3′-alternative splicing and intron retention. The dataset is derived by comparing the nucleotide and protein sequences available for a given gene for evidence of AS. Additional features such as the tissue specificity of the mRNA, the protein domain contained by exons, the GC-ratio of exons, the repeats contained within the exons, and the Gene Ontology are annotated computationally for each exonic region that is alternatively spliced. Motivated by a previous investigation of AS-related motifs such as exonic splicing enhancer and exonic splicing silencer, this resource also provides a means of identifying motifs candidates and this should help to identify potential regulatory mechanisms within a particular exonic sequence set and its two flanking intronic sequence sets. This is carried out using motif discovery tools to identify motif candidates related to alternative splicing regulation and together with a secondary structure prediction tool, will help in the identification of the structural properties of such regulatory motifs. The integrated resource is now available on http://SpliceInfo.mbc.NCTU.edu.tw/.
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Affiliation(s)
- Hsien-Da Huang
- Department of Biological Science and Technology, Institute of Bioinformatics, National Chiao Tung University, Hsin-Chu 300, Taiwan
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21
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Abstract
ECgene provides annotation for gene structure, function and expression, taking alternative splicing events into consideration. The gene-modeling algorithm combines the genome-based expressed sequence tag (EST) clustering and graph-theoretic transcript assembly procedures. The website provides several viewers and applications that have many unique features useful for the analysis of the transcript structure and gene expression. The summary viewer shows the gene summary and the essence of other annotation programs. The genome browser and the transcript viewer are available for comparing the gene structure of splice variants. Changes in the functional domains by alternative splicing can be seen at a glance in the transcript viewer. We also provide two unique ways of analyzing gene expression. The SAGE tags deduced from the assembled transcripts are used to delineate quantitative expression patterns from SAGE libraries available publically. Furthermore, the cDNA libraries of EST sequences in each cluster are used to infer qualitative expression patterns. It should be noted that the ECgene website provides annotation for the whole transcriptome, not just the alternatively spliced genes. Currently, ECgene supports the human, mouse and rat genomes. The ECgene suite of tools and programs is available at http://genome.ewha.ac.kr/ECgene/.
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Affiliation(s)
- Pora Kim
- Division of Molecular Life Sciences, Ewha Womans University, Seoul 120-750, Korea
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22
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Foissac S, Schiex T. Integrating alternative splicing detection into gene prediction. BMC Bioinformatics 2005; 6:25. [PMID: 15705189 PMCID: PMC550657 DOI: 10.1186/1471-2105-6-25] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2004] [Accepted: 02/10/2005] [Indexed: 11/24/2022] Open
Abstract
Background Alternative splicing (AS) is now considered as a major actor in transcriptome/proteome diversity and it cannot be neglected in the annotation process of a new genome. Despite considerable progresses in term of accuracy in computational gene prediction, the ability to reliably predict AS variants when there is local experimental evidence of it remains an open challenge for gene finders. Results We have used a new integrative approach that allows to incorporate AS detection into ab initio gene prediction. This method relies on the analysis of genomically aligned transcript sequences (ESTs and/or cDNAs), and has been implemented in the dynamic programming algorithm of the graph-based gene finder EuGÈNE. Given a genomic sequence and a set of aligned transcripts, this new version identifies the set of transcripts carrying evidence of alternative splicing events, and provides, in addition to the classical optimal gene prediction, alternative optimal predictions (among those which are consistent with the AS events detected). This allows for multiple annotations of a single gene in a way such that each predicted variant is supported by a transcript evidence (but not necessarily with a full-length coverage). Conclusions This automatic combination of experimental data analysis and ab initio gene finding offers an ideal integration of alternatively spliced gene prediction inside a single annotation pipeline.
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MESH Headings
- Algorithms
- Alternative Splicing
- Arabidopsis/genetics
- Codon
- Computer Graphics
- DNA, Complementary/metabolism
- Databases, Genetic
- Databases, Nucleic Acid
- Databases, Protein
- Exons
- Expressed Sequence Tags
- Gene Expression Profiling
- Genes, Plant
- Genome
- Genome, Human
- Genomics
- Humans
- Introns
- Models, Genetic
- Proteomics/methods
- RNA Splice Sites
- Sequence Alignment
- Sequence Analysis, Protein
- Sequence Analysis, RNA
- Software
- Transcription, Genetic
- User-Computer Interface
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Affiliation(s)
- Sylvain Foissac
- Unité de Biométrie et Intelligence Artificielle, INRA, 31326 Castanet Tolosan, France
| | - Thomas Schiex
- Unité de Biométrie et Intelligence Artificielle, INRA, 31326 Castanet Tolosan, France
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23
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Kalnina Z, Zayakin P, Silina K, Linē A. Alterations of pre-mRNA splicing in cancer. Genes Chromosomes Cancer 2005; 42:342-57. [PMID: 15648050 DOI: 10.1002/gcc.20156] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Recent genomewide analyses of alternative splicing (AS) indicate that up to 70% of human genes may have alternative splice forms, suggesting that AS together with various posttranslational modifications plays a major role in the production of proteome complexity. Splice-site selection under normal physiological conditions is regulated in the developmental stage in a tissue type-specific manner by changing the concentrations and the activity of splicing regulatory proteins. Whereas spliceosomal errors resulting in the production of aberrant transcripts rarely occur in normal cells, they seem to be an intrinsic property of cancer cells. Changes in splice-site selection have been observed in various types of cancer and may affect genes implicated in tumor progression (for example, CD44, MDM2, and FHIT) and in susceptibility to cancer (for example, BRCA1 and APC). Splicing defects can arise from inherited or somatic mutations in cis-acting regulatory elements (splice donor, acceptor and branch sites, and exonic and intronic splicing enhancers and silencers) or variations in the composition, concentration, localization, and activity of regulatory proteins. This may lead to altered efficiency of splice-site recognition, resulting in overexpression or down-regulation of certain splice variants, a switch in splice-site usage, or failure to recognize splice sites correctly, resulting in cancer-specific splice forms. At least in some cases, changes in splicing have been shown to play a functionally significant role in tumorigenesis, either by inactivating tumor suppressors or by gain of function of proteins promoting tumor development. Moreover, cancer-specific splicing events may generate novel epitopes that can be recognized by the host's immune system as cancer specific and may serve as targets for immunotherapy. Thus, the identification of cancer-specific splice forms provides a novel source for the discovery of diagnostic or prognostic biomarkers and tumor antigens suitable as targets for therapeutic intervention.
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Affiliation(s)
- Zane Kalnina
- Biomedical Research and Study Centre, University of Latvia, Ratsupites St 1, LV-1067 Riga, Latvia
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24
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Leipzig J, Pevzner P, Heber S. The Alternative Splicing Gallery (ASG): bridging the gap between genome and transcriptome. Nucleic Acids Res 2004; 32:3977-83. [PMID: 15292448 PMCID: PMC506815 DOI: 10.1093/nar/gkh731] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Alternative splicing essentially increases the diversity of the transcriptome and has important implications for physiology, development and the genesis of diseases. Conventionally, alternative splicing is investigated in a case-by-case fashion, but this becomes cumbersome and error prone if genes show a huge abundance of different splice variants. We use a different approach and integrate all transcripts derived from a gene into a single splicing graph. Each transcript corresponds to a path in the graph, and alternative splicing is displayed by bifurcations. This representation preserves the relationships between different splicing variants and allows us to investigate systematically all possible putative transcripts. We built a database of splicing graphs for human genes, using transcript information from various major sources (Ensembl, RefSeq, STACK, TIGR and UniGene). A Web interface allows users to display the splicing graphs, to interactively assemble transcripts and to access their sequences as well as neighboring genomic regions. We also provide for each gene an exhaustive pre-computed catalog of putative transcripts--in total more than 1.2 million sequences. We found that approximately 65% of the investigated genes show evidence for alternative splicing, and in 5% of the cases, a single gene might produce over 100 transcripts.
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Affiliation(s)
- Jeremy Leipzig
- Department of Computer Science, College of Engineering, North Carolina State University, Raleigh, NC 27695-7566, USA
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25
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Abstract
Alternative splicing is now commonly thought to affect more than half of all human genes. Recent studies have investigated not only the scope but also the biological impact of alternative splicing on a large scale, revealing that its role in generating proteome diversity may be augmented by a role in regulation. For instance, protein function can be regulated by the removal of interaction or localization domains by alternative splicing. Alternative splicing can also regulate gene expression by splicing transcripts into unproductive mRNAs targeted for degradation. To fully understand the scope of alternative splicing, we must also determine how many of the predicted splice variants represent functional forms. Comparisons of alternative splicing between human and mouse genes show that predominant splice variants are usually conserved, but rare variants are less commonly shared. Evolutionary conservation of splicing patterns suggests functional importance and provides insight into the evolutionary history of alternative splicing.
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Affiliation(s)
- Liana F Lareau
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
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26
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Desiere F. Towards a systems biology understanding of human health: Interplay between genotype, environment and nutrition. BIOTECHNOLOGY ANNUAL REVIEW 2004; 10:51-84. [PMID: 15504703 DOI: 10.1016/s1387-2656(04)10003-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Sequencing of the human genome has opened the door to the most exciting new era for the holistic system description of human health. It is now possible to study the underlying mechanisms of human health in relation to diet and other environmental factors such as drugs and toxic pollutants. Technological advances make it feasible to envisage that in the future personalized drug treatment and dietary advice and possibly tailored food products can be used for promoting optimal health on an individual basis, in relation to genotype and lifestyle. Life-Science research has in the past very much focused on diseases and how to reestablish human health after illness. Today, the role of food and nutrition in human health and especially prevention of illness is gaining recognition. Diseases of modern civilization, such as diabetes, heart disease and cancer have been shown to be effected by dietary patterns. The risk of disease is often associated with genetic polymorphisms, but the effect is dependent on dietary intake and nutritional status. To understand the link between diet and health, nutritional-research must cover a broad range of areas, from the molecular level to whole body studies. Therefore it provides an excellent example of integrative biology requiring a systems biology approach. The current state and implications of systems biology in the understanding of human health are reviewed. It becomes clear that a complete mechanistic description of the human organism is not yet possible. However, recent advances in systems biology provide a trajectory for future research in order to improve health of individuals and populations. Disease prevention through personalized nutrition will become more important as the obvious avenue of research in life sciences and more focus will need to be put upon those natural ways of disease prevention. In particular, the new discipline of nutrigenomics, which investigates how nutrients interact with humans, taking predetermined genetic factors into account, will mediate new insights into human health that will finally have significant positive impact on our quality of life.
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Affiliation(s)
- Frank Desiere
- Nestlé Research Center, P.O. Box 44, 1000 Lausanne 26, Switzerland.
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27
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Vanier MT, Deck P, Stutzmann J, Gendry P, Arnold C, Dirrig-Grosch S, Kedinger M, Launay JF. Expression and distribution of distinct variants of E-MAP-115 during proliferation and differentiation of human intestinal epithelial cells. CELL MOTILITY AND THE CYTOSKELETON 2003; 55:221-31. [PMID: 12845596 DOI: 10.1002/cm.10124] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Epithelial cell proliferation and differentiation occur concomitant with striking remodeling of the cytoskeleton. Microtubules (MTs) play important roles in these processes, during which the MTs themselves are reorganized and stabilized by microtubule-associated proteins (MAPs). Among the proteins classified as structural MAPs, E-MAP-115 (also named ensconsin) is preferentially expressed in cells of epithelial origin. The aims of this study were, first, to determine if E-MAP-115, like other MAPs, is expressed as different isoforms during differentiation and, second, to perform a detailed analysis of the expression and distribution of any E-MAP-115 variants detected in intestinal epithelial cells during their polarization/differentiation. It was our expectation that these data would help us to develop hypotheses concerning the role of this MAP in epithelial development. We report the expression of three E-MAP-115 transcripts encoding isoforms of 115, 105, and 95 kDa; two display an expression gradient inverse to the third one as Caco-2 cells progress from proliferation through the stages of differentiation. To monitor the proteins produced from each transcript, we used purified polyclonal antibodies against synthetic peptides contained within the 115, 105, and 95 kDa isoforms to assay proliferating and differentiating CaCo-2 cells. Our results indicate that the expression and MT-binding capacity of the 115, 105, and 95 kDa isoforms vary upon proliferation/differentiation of the cells. E-MAP-115 proteins colocalize with MTs in proliferative and differentiated Caco-2 cells; in vivo, they are expressed in both crypt and villus epithelial cells where they are mainly concentrated at the apical pole of the cells.
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