scholarly journals Exploring the functional impact of alternative splicing on human protein isoforms using available annotation sources

2019 ◽  
Vol 20 (5) ◽  
pp. 1754-1768 ◽  
Author(s):  
Dinanath Sulakhe ◽  
Mark D’Souza ◽  
Sheng Wang ◽  
Sandhya Balasubramanian ◽  
Prashanth Athri ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Contextual Information ◽  
Single Gene ◽  
Cellular Responses ◽  
Protein Isoforms ◽  
Modeling And Analysis ◽  
The Public ◽  
Alternatively Spliced ◽  
Cellular Pathways ◽  
Genome Analyses

Abstract In recent years, the emphasis of scientific inquiry has shifted from whole-genome analyses to an understanding of cellular responses specific to tissue, developmental stage or environmental conditions. One of the central mechanisms underlying the diversity and adaptability of the contextual responses is alternative splicing (AS). It enables a single gene to encode multiple isoforms with distinct biological functions. However, to date, the functions of the vast majority of differentially spliced protein isoforms are not known. Integration of genomic, proteomic, functional, phenotypic and contextual information is essential for supporting isoform-based modeling and analysis. Such integrative proteogenomics approaches promise to provide insights into the functions of the alternatively spliced protein isoforms and provide high-confidence hypotheses to be validated experimentally. This manuscript provides a survey of the public databases supporting isoform-based biology. It also presents an overview of the potential global impact of AS on the human canonical gene functions, molecular interactions and cellular pathways.

scholarly journals Influence of Intron Length on Alternative Splicing of CD44

1998 ◽  
Vol 18 (10) ◽  
pp. 5930-5941 ◽  
Author(s):  
Martyn V. Bell ◽  
Alison E. Cowper ◽  
Marie-Paule Lefranc ◽  
John I. Bell ◽  
Gavin R. Screaton
Keyword(s):  
Alternative Splicing ◽  
Genomic Structure ◽  
Single Gene ◽  
Intron Length ◽  
Protein Isoforms ◽  
Major Influence ◽  
Eukaryotic Genes ◽  
Alternatively Spliced ◽  
Alternatively Spliced Exons

ABSTRACT Although the splicing of transcripts from most eukaryotic genes occurs in a constitutive fashion, some genes can undergo a process of alternative splicing. This is a genetically economical process which allows a single gene to give rise to several protein isoforms by the inclusion or exclusion of sequences into or from the mature mRNA. CD44 provides a unique example; more than 1,000 possible isoforms can be produced by the inclusion or exclusion of a central tandem array of 10 alternatively spliced exons. Certain alternatively spliced exons have been ascribed specific functions; however, independent regulation of the inclusion or skipping of each of these exons would clearly demand an extremely complex regulatory network. Such a network would involve the interaction of many exon-specific trans-acting factors with the pre-mRNA. Therefore, to assess whether the exons are indeed independently regulated, we have examined the alternative exon content of a large number of individual CD44 cDNA isoforms. This analysis shows that the downstream alternatively spliced exons are favored over those lying upstream and that alternative exons are often included in blocks rather than singly. Using a novel in vivo alternative splicing assay, we show that intron length has a major influence upon the alternative splicing of CD44. We propose a kinetic model in which short introns may overcome the poor recognition of alternatively spliced exons. These observations suggest that for CD44, intron length has been exploited in the evolution of the genomic structure to enable tissue-specific patterns of splicing to be maintained.

scholarly journals Alternative splicing in endothelial cells: novel therapeutic opportunities in cancer angiogenesis

2020 ◽  
Vol 39 (1) ◽  
Author(s):  
Anna Di Matteo ◽  
Elisa Belloni ◽  
Davide Pradella ◽  
Ambra Cappelletto ◽  
Nina Volf ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Human Cancer ◽  
Single Gene ◽  
Predictive Biomarkers ◽  
Protein Isoforms ◽  
Therapeutic Interventions ◽  
Cancer Therapies ◽  
Functional Changes ◽  
Splicing Regulators ◽  
Multiple Protein

AbstractAlternative splicing (AS) is a pervasive molecular process generating multiple protein isoforms, from a single gene. It plays fundamental roles during development, differentiation and maintenance of tissue homeostasis, while aberrant AS is considered a hallmark of multiple diseases, including cancer. Cancer-restricted AS isoforms represent either predictive biomarkers for diagnosis/prognosis or targets for anti-cancer therapies. Here, we discuss the contribution of AS regulation in cancer angiogenesis, a complex process supporting disease development and progression. We consider AS programs acting in a specific and non-redundant manner to influence morphological and functional changes involved in cancer angiogenesis. In particular, we describe relevant AS variants or splicing regulators controlling either secreted or membrane-bound angiogenic factors, which may represent attractive targets for therapeutic interventions in human cancer.

Alternative splicing can lead to chaos

2015 ◽  
Vol 13 (01) ◽  
pp. 1540003 ◽  
Author(s):  
Vitaly A. Likhoshvai ◽  
Vladislav V. Kogai ◽  
Stanislav I. Fadeev ◽  
Tamara M. Khlebodarova
Keyword(s):  
Alternative Splicing ◽  
Chaotic Dynamics ◽  
Single Gene ◽  
Regulatory Protein ◽  
Genetic System ◽  
Feedback Mechanism ◽  
Regulatory Proteins ◽  
Gene Encoding ◽  
Regulation Type ◽  
Alternatively Spliced

Alternative splicing is a widespread phenomenon in higher eukaryotes, where it serves as a mechanism to increase the functional diversity of proteins. This phenomenon has been described for different classes of proteins, including transcription regulatory proteins. We demonstrated that in the simplest genetic system model the formation of the alternatively spliced isoforms with opposite functions (activators and repressors) could be a cause of transition to chaotic dynamics. Under the simplest genetic system we understand a system consisting of a single gene encoding the structure of a transcription regulatory protein whose expression is regulated by a feedback mechanism. As demonstrated by numerical analysis of the models, if the synthesized isoforms regulate the expression of their own gene acting through different sites and independently of each other, for the generation of chaotic dynamics it is sufficient that the regulatory proteins have a dimeric structure. If regulatory proteins act through one site, the chaotic dynamics is generated in the system only when the repressor protein is either a tetrameric or a higher-dimensional multimer. In this case the activator can be a dimer. It was also demonstrated that if the transcription factor isoforms exhibit either activating or inhibiting activity and are lower-dimensional multimers (< 4), independently of the regulation type the model demonstrates either cyclic or stationary trajectories.

scholarly journals An alternatively spliced zebrafish jnk1a transcript has an essential and non-redundant role in development of the first heart field derived proximal ventricular chamber

2019 ◽  
Author(s):  
A Santos-Ledo ◽  
S Washer ◽  
T Dhanaseelan ◽  
P Chrystal ◽  
T Papoutsi ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Heart Development ◽  
Planar Cell Polarity ◽  
Cardiac Development ◽  
Single Gene ◽  
Jun Kinase ◽  
Downstream Effectors ◽  
Heart Malformation ◽  
Alternatively Spliced ◽  
First Heart Field

AbstractAlternative splicing is a ubiquitous mechanism for producing different mRNA species from a single gene, resulting in proteomic diversity. Despite potential for regulating embryogenesis, its developmental role remains under-investigated. The Jun kinase (Jnk) genes, considered downstream effectors of the non-canonical Wnt planar cell polarity pathway, utilise extensive and evolutionarily-conserved alternative splicing. Although many PCP members are associated with heart malformation, the role of Jnk genes in cardiac development, and specifically which alternatively spliced transcripts orchestrate these processes, remain unknown. In this study we exploit the jnk1 duplication and subspecialisation found in zebrafish to reveal an essential and non-redundant requirement for jnk1a in cardiac development. We characterise alternatively spliced jnk1a/jnk1b transcripts and demonstrate that hypoplasia of the proximal ventricular component, which corresponds to human hypoplastic left ventricle, can only be rescued by the jnk1a Ex7 Lg transcript. These studies highlight the importance of Jnk signalling and alternative splicing in heart development

scholarly journals Splicing Regulators and Their Roles in Cancer Biology and Therapy

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Maria Roméria da Silva ◽  
Gabriela Alves Moreira ◽  
Ronni Anderson Gonçalves da Silva ◽  
Éverton de Almeida Alves Barbosa ◽  
Raoni Pais Siqueira ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Cancer Biology ◽  
Single Gene ◽  
Tumor Biology ◽  
Sr Proteins ◽  
Protein Isoforms ◽  
Protein Expression Pattern ◽  
Regulatory Factors ◽  
Impact Pathways ◽  
Splicing Regulators

Alternative splicing allows cells to expand the encoding potential of their genomes. In this elegant mechanism, a single gene can yield protein isoforms with even antagonistic functions depending on the cellular physiological context. Alterations in splicing regulatory factors activity in cancer cells, however, can generate an abnormal protein expression pattern that promotes growth, survival, and other processes, which are relevant to tumor biology. In this review, we discuss dysregulated alternative splicing events and regulatory factors that impact pathways related to cancer. The SR proteins and their regulatory kinases SRPKs and CLKs have been frequently found altered in tumors and are examined in more detail. Finally, perspectives that support splicing machinery as target for the development of novel anticancer therapies are discussed.

scholarly journals Abnormalities in alternative splicing in diabetes: therapeutic targets

2017 ◽  
Vol 59 (2) ◽  
pp. R93-R107 ◽  
Author(s):  
Zodwa Dlamini ◽  
Fortunate Mokoena ◽  
Rodney Hull
Keyword(s):  
Alternative Splicing ◽  
Single Gene ◽  
Treatment Options ◽  
Cell Mass ◽  
Biological Significance ◽  
Cost Effective ◽  
Significant Loss ◽  
Protein Isoforms ◽  
Β Cell ◽  
Therapeutic Tools

Diabetes mellitus (DM) is a non-communicable, metabolic disorder that affects 416 million individuals worldwide. Type 2 diabetes contributes to a vast 85–90% of the diabetes incidences while 10–15% of patients suffer from type 1 diabetes. These two predominant forms of DM cause a significant loss of functional pancreatic β-cell mass causing different degrees of insulin deficiency, most likely, due to increased β-cell apoptosis. Treatment options involve the use of insulin sensitisers, α-glucosidase inhibitors, and β-cell secretagogues which are often expensive, limited in efficacy and carry detrimental adverse effects. Cost-effective options for treatment exists in the form of herbal drugs, however, scientific validations of these widely used medicinal plants are still underway. Alternative splicing (AS) is a co-ordinated post-transcriptional process in which a single gene generates multiple mRNA transcripts which results in increased amounts of functionally different protein isoforms and in some cases aberrant splicing leads to metabolic disease. In this review, we explore the association of AS with metabolic alterations in DM and the biological significance of the abnormal splicing of some pathogenic diabetes-related genes. An understanding of the molecular mechanism behind abnormally spliced transcripts will aid in the development of new diagnostic, prognostic and therapeutic tools.

scholarly journals Evolutionary conservation of the structure and expression of alternatively spliced Ultrabithorax isoforms from Drosophila.

Genetics ◽  
1994 ◽  
Vol 136 (3) ◽  
pp. 965-977
Author(s):  
H M Bomze ◽  
A J López
Keyword(s):  
Alternative Splicing ◽  
Protein Function ◽  
Developmental Regulation ◽  
Expression Patterns ◽  
Proximal Region ◽  
Amino Acid Sequences ◽  
Drosophila Virilis ◽  
Protein Isoforms ◽  
Developmentally Regulated ◽  
Alternatively Spliced

Abstract In Drosophila melanogaster, alternatively spliced mRNAs from the homeotic gene Ultrabithorax (Ubx) encode a family of structurally distinct homeoprotein isoforms. The developmentally regulated expression patterns of these isoforms suggest that they have specialized stage- and tissue-specific functions. To evaluate the functional importance of UBX isoform diversity and gain clues to the mechanism that regulates processing of Ubx RNAs, we have investigated whether the Ubx RNAs of other insects undergo similar alternative splicing. We have isolated and characterized Ubx cDNA fragments from D. melanogaster, Drosophila pseudoobscura, Drosophila hydei and Drosophila virilis, species separated by as much as 60 million years of evolution, and have found that three aspects of Ubx RNA processing have been conserved. (1) These four species exhibit identical patterns of optional exon use in a region adjacent to the homeodomain. (2) These four species produce the same family of UBX protein isoforms with identical amino acid sequences in the optional exons, even though the common amino-proximal region has undergone substantial divergence. The nucleotide sequences of the optional exons, including third positions of rare codons, have also been conserved strongly, suggesting functional constraints that are not limited to coding potential. (3) The tissue- and stage-specific patterns of expression of different UBX isoforms are identical among these Drosophila species, indicating that the developmental regulation of the alternative splicing events has also been conserved. These findings argue for an important role of alternative splicing in Ubx function. We discuss the implications of these results for models of UBX protein function and the mechanism of alternative splicing.

scholarly journals Identification of Genomewide Alternative Splicing Events in Sequential, Isogenic Clinical Isolates of Candida albicans Reveals a Novel Mechanism of Drug Resistance and Tolerance to Cellular Stresses

mSphere ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Suraya Muzafar ◽  
Ravi Datta Sharma ◽  
Abdul Haseeb Shah ◽  
Naseem A. Gaur ◽  
Ujjaini Dasgupta ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Candida Albicans ◽  
Alternative Splicing ◽  
Rna Sequencing ◽  
Single Gene ◽  
Drug Susceptibility ◽  
Protein Isoforms ◽  
Sequencing Data ◽  
Splice Isoforms ◽  
Content Type

ABSTRACT Alternative splicing (AS)—a process by which a single gene gives rise to different protein isoforms in eukaryotes—has been implicated in many basic cellular processes, but little is known about its role in drug resistance and fungal pathogenesis. The most common human fungal pathogen, Candida albicans, has introns in 4 to 6% of its genes, the functions of which remain largely unknown. Here, we report AS regulating drug resistance in C. albicans. Comparative RNA-sequencing of two different sets of sequential, isogenic azole-sensitive and -resistant isolates of C. albicans revealed differential expression of splice isoforms of 14 genes. One of these was the superoxide dismutase gene SOD3, which contains a single intron. The sod3Δ/Δ mutant was susceptible to the antifungals amphotericin B (AMB) and menadione (MND). While AMB susceptibility was rescued by overexpression of both the spliced and unspliced SOD3 isoforms, only the spliced isoform could overcome MND susceptibility, demonstrating the functional relevance of this splicing in developing drug resistance. Furthermore, unlike AMB, MND inhibits SOD3 splicing and acts as a splicing inhibitor. Consistent with these observations, MND exposure resulted in increased levels of unspliced SOD3 isoform that are unable to scavenge reactive oxygen species (ROS), resulting in increased drug susceptibility. Collectively, these observations suggest that AS is a novel mechanism for stress adaptation and overcoming drug susceptibility in C. albicans. IMPORTANCE The emergence of resistance in Candida albicans, an opportunistic pathogen, against the commonly used antifungals is becoming a major obstacle in its treatment. The necessity to identify new drug targets demands fundamental insights into the mechanisms used by this organism to develop drug resistance. C. albicans has introns in 4 to 6% of its genes, the functions of which remain largely unknown. Using the RNA-sequencing data from isogenic pairs of azole-sensitive and -resistant isolates of C. albicans, here, we show how C. albicans uses modulations in mRNA splicing to overcome antifungal drug stress.

scholarly journals RNA Interference Knockdown of hU2AF35 Impairs Cell Cycle Progression and Modulates Alternative Splicing of Cdc25 Transcripts

2006 ◽  
Vol 17 (10) ◽  
pp. 4187-4199 ◽  
Author(s):  
Teresa Raquel Pacheco ◽  
Luís Ferreira Moita ◽  
Anita Quintal Gomes ◽  
Nir Hacohen ◽  
Maria Carmo-Fonseca
Keyword(s):  
Cell Cycle ◽  
Alternative Splicing ◽  
Rna Interference ◽  
Cell Cycle Progression ◽  
Protein Isoforms ◽  
Cell Cycle Gene ◽  
Mitotic Progression ◽  
Cycle Progression ◽  
Specific Subset ◽  
Alternatively Spliced

U2AF is a heterodimeric splicing factor composed of a large (U2AF65) and a small (U2AF35) subunit. In humans, alternative splicing generates two U2AF35 variants, U2AF35a and U2AF35b. Here, we used RNA interference to specifically ablate the expression of each isoform in HeLa cells. Our results show that knockdown of the major U2AF35a isoform reduced cell viability and impaired mitotic progression, leading to accumulation of cells in prometaphase. Microarray analysis revealed that knockdown of U2AF35a affected the expression level of ∼500 mRNAs, from which >90% were underrepresented relative to the control. Among mRNAs underrepresented in U2AF35a-depleted cells we identified an essential cell cycle gene, Cdc27, for which there was an increase in the ratio between unspliced and spliced RNA and a significant reduction in protein level. Furthermore, we show that depletion of either U2AF35a or U2AF35b altered the ratios of alternatively spliced isoforms of Cdc25B and Cdc25C transcripts. Taken together our results demonstrate that U2AF35a is essential for HeLa cell division and suggest a novel role for both U2AF35 protein isoforms as regulators of alternative splicing of a specific subset of genes.

A saga of cancer epigenetics: linking epigenetics to alternative splicing

2017 ◽  
Vol 474 (6) ◽  
pp. 885-896 ◽  
Author(s):  
Sathiya Pandi Narayanan ◽  
Smriti Singh ◽  
Sanjeev Shukla
Keyword(s):  
Alternative Splicing ◽  
Rna Polymerase Ii ◽  
Cancer Progression ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Epigenetic Modifications ◽  
Protein Isoforms ◽  
Epigenetic Alterations ◽  
Cancer Epigenetics ◽  
Alternatively Spliced

The discovery of an increasing number of alternative splicing events in the human genome highlighted that ∼94% of genes generate alternatively spliced transcripts that may produce different protein isoforms with diverse functions. It is now well known that several diseases are a direct and indirect consequence of aberrant splicing events in humans. In addition to the conventional mode of alternative splicing regulation by ‘cis’ RNA-binding sites and ‘trans’ RNA-binding proteins, recent literature provides enormous evidence for epigenetic regulation of alternative splicing. The epigenetic modifications may regulate alternative splicing by either influencing the transcription elongation rate of RNA polymerase II or by recruiting a specific splicing regulator via different chromatin adaptors. The epigenetic alterations and aberrant alternative splicing are known to be associated with various diseases individually, but this review discusses/highlights the latest literature on the role of epigenetic alterations in the regulation of alternative splicing and thereby cancer progression. This review also points out the need for further studies to understand the interplay between epigenetic modifications and aberrant alternative splicing in cancer progression.

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