scholarly journals Assessing the functional relevance of splice isoforms

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Fernando Pozo ◽  
Laura Martinez-Gomez ◽  
Thomas A Walsh ◽  
José Manuel Rodriguez ◽  
Tomas Di Domenico ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Messenger Rna ◽  
Large Scale ◽  
Somatic Mutations ◽  
Species Conservation ◽  
Purifying Selection ◽  
Protein Isoforms ◽  
Splice Isoforms ◽  
Population Genetic Variation ◽  
Functional Relevance

Abstract Alternative splicing of messenger RNA can generate an array of mature transcripts, but it is not clear how many go on to produce functionally relevant protein isoforms. There is only limited evidence for alternative proteins in proteomics analyses and data from population genetic variation studies indicate that most alternative exons are evolving neutrally. Determining which transcripts produce biologically important isoforms is key to understanding isoform function and to interpreting the real impact of somatic mutations and germline variations. Here we have developed a method, TRIFID, to classify the functional importance of splice isoforms. TRIFID was trained on isoforms detected in large-scale proteomics analyses and distinguishes these biologically important splice isoforms with high confidence. Isoforms predicted as functionally important by the algorithm had measurable cross species conservation and significantly fewer broken functional domains. Additionally, exons that code for these functionally important protein isoforms are under purifying selection, while exons from low scoring transcripts largely appear to be evolving neutrally. TRIFID has been developed for the human genome, but it could in principle be applied to other well-annotated species. We believe that this method will generate valuable insights into the cellular importance of alternative splicing.

scholarly journals AUGmenting the proteome: Novel initiation codons and their role in protein isoform generation

2015 ◽  
Vol 37 (2) ◽  
pp. 19-23
Author(s):  
Mark J. Coldwell ◽  
Joanne L. Cowan
Keyword(s):  
Alternative Splicing ◽  
Translation Initiation ◽  
Messenger Rna ◽  
Genetic Material ◽  
Protein Sequencing ◽  
Protein Isoforms ◽  
Alternative Promoters ◽  
Alternative Translation ◽  
Initial Hypothesis ◽  
Protein Isoform

As the field of molecular biology developed, and the understanding of how inherited genetic material results in the expression of proteins was established, the initial hypothesis was that one gene gave rise to one protein1. As researchers delved deeper into the organization of the genetic code and advances in messenger RNA (mRNA) and protein sequencing were subsequently made, it has become abundantly clear that multiple mechanisms exist meaning that many mRNAs encode more than one version of a protein. Although alternative promoters and alternative splicing play a considerable role in the generation of protein isoforms, in this article we discuss how usage of alternative translation initiation codons in eukaryotes can also lead to an expanded proteome.

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 Proteomics: The protein complement of the genome

2003 ◽  
Vol 25 (1) ◽  
pp. 7-9
Author(s):  
Hannes Ponstingl ◽  
Janet M. Thornton
Keyword(s):  
Messenger Rna ◽  
Protein Separation ◽  
Large Scale ◽  
Protein Complexes ◽  
Protein Isoforms ◽  
Structural Proteomics ◽  
Protein Markers ◽  
Proteomics Data ◽  
Single Experiment ◽  
Large Sets

Recent advances in protein separation technology and mass spectrometry (MS) have enabled the systematic identification and quantification of large sets of proteins from an organelle, cell type or organism. In principle, protein isoforms, enzymically modified variants and protein complexes can be studied, for instance, at a certain stage in development or in response to stress or more subtle changes of the environment. An important pre-clinical application is the search for protein markers in body fluids for diagnostic purposes. Such proteomics studies can be performed increasingly at high-throughput rates that are reminiscent of those of genomic sequencing or the monitoring of messenger RNA levels. Thus, large sets of proteins can be monitored simultaneously in a single experiment. Proteomics data will increasingly be followed up by investigations of the three-dimensional structures of proteins and protein complexes at atomic detail in large-scale structural proteomics projects. We attempt in this article to give a flavour of what to us seem important experimental developments and to point to links with bioinformatics resources where appropriate.

scholarly journals Mutational patterns and clonal evolution from diagnosis to relapse in pediatric acute lymphoblastic leukemia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shumaila Sayyab ◽  
Anders Lundmark ◽  
Malin Larsson ◽  
Markus Ringnér ◽  
Sara Nystedt ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Large Scale ◽  
Somatic Mutations ◽  
Lymphoblastic Leukemia ◽  
Clonal Evolution ◽  
Point Mutations ◽  
Driver Genes ◽  
Protein Coding ◽  
Pediatric Acute Lymphoblastic Leukemia ◽  
Evolutionary Trajectories

AbstractThe mechanisms driving clonal heterogeneity and evolution in relapsed pediatric acute lymphoblastic leukemia (ALL) are not fully understood. We performed whole genome sequencing of samples collected at diagnosis, relapse(s) and remission from 29 Nordic patients. Somatic point mutations and large-scale structural variants were called using individually matched remission samples as controls, and allelic expression of the mutations was assessed in ALL cells using RNA-sequencing. We observed an increased burden of somatic mutations at relapse, compared to diagnosis, and at second relapse compared to first relapse. In addition to 29 known ALL driver genes, of which nine genes carried recurrent protein-coding mutations in our sample set, we identified putative non-protein coding mutations in regulatory regions of seven additional genes that have not previously been described in ALL. Cluster analysis of hundreds of somatic mutations per sample revealed three distinct evolutionary trajectories during ALL progression from diagnosis to relapse. The evolutionary trajectories provide insight into the mutational mechanisms leading relapse in ALL and could offer biomarkers for improved risk prediction in individual patients.

scholarly journals Neurodegenerative diseases: a hotbed for splicing defects and the potential therapies

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Dunhui Li ◽  
Craig Stewart McIntosh ◽  
Frank Louis Mastaglia ◽  
Steve Donald Wilton ◽  
May Thandar Aung-Htut
Keyword(s):  
Alternative Splicing ◽  
Neurodegenerative Diseases ◽  
Messenger Rna ◽  
Muscular Atrophy ◽  
Single Gene ◽  
Synaptic Function ◽  
Coding Regions ◽  
Splicing Defects ◽  
The Impact ◽  
Splicing Patterns

AbstractPrecursor messenger RNA (pre-mRNA) splicing is a fundamental step in eukaryotic gene expression that systematically removes non-coding regions (introns) and ligates coding regions (exons) into a continuous message (mature mRNA). This process is highly regulated and can be highly flexible through a process known as alternative splicing, which allows for several transcripts to arise from a single gene, thereby greatly increasing genetic plasticity and the diversity of proteome. Alternative splicing is particularly prevalent in neuronal cells, where the splicing patterns are continuously changing to maintain cellular homeostasis and promote neurogenesis, migration and synaptic function. The continuous changes in splicing patterns and a high demand on many cis- and trans-splicing factors contribute to the susceptibility of neuronal tissues to splicing defects. The resultant neurodegenerative diseases are a large group of disorders defined by a gradual loss of neurons and a progressive impairment in neuronal function. Several of the most common neurodegenerative diseases involve some form of splicing defect(s), such as Alzheimer’s disease, Parkinson’s disease and spinal muscular atrophy. Our growing understanding of RNA splicing has led to the explosion of research in the field of splice-switching antisense oligonucleotide therapeutics. Here we review our current understanding of the effects alternative splicing has on neuronal differentiation, neuronal migration, synaptic maturation and regulation, as well as the impact on neurodegenerative diseases. We will also review the current landscape of splice-switching antisense oligonucleotides as a therapeutic strategy for a number of common neurodegenerative disorders.

scholarly journals Genome-wide Analysis of Alternative Pre-mRNA Splicing

2007 ◽  
Vol 283 (3) ◽  
pp. 1229-1233 ◽  
Author(s):  
Claudia Ben-Dov ◽  
Britta Hartmann ◽  
Josefin Lundgren ◽  
Juan Valcárcel
Keyword(s):  
Alternative Splicing ◽  
Large Scale ◽  
Mrna Splicing ◽  
Diagnostic Tools ◽  
Primary Transcript ◽  
Genome Wide ◽  
Human Genes ◽  
Multicellular Organisms ◽  
Eukaryotic Genomes ◽  
Key Questions

Alternative splicing of mRNA precursors allows the synthesis of multiple mRNAs from a single primary transcript, significantly expanding the information content and regulatory possibilities of higher eukaryotic genomes. High-throughput enabling technologies, particularly large-scale sequencing and splicing-sensitive microarrays, are providing unprecedented opportunities to address key questions in this field. The picture emerging from these pioneering studies is that alternative splicing affects most human genes and a significant fraction of the genes in other multicellular organisms, with the potential to greatly influence the evolution of complex genomes. A combinatorial code of regulatory signals and factors can deploy physiologically coherent programs of alternative splicing that are distinct from those regulated at other steps of gene expression. Pre-mRNA splicing and its regulation play important roles in human pathologies, and genome-wide analyses in this area are paving the way for improved diagnostic tools and for the identification of novel and more specific pharmaceutical targets.

Computation-assisted targeted proteomics of alternative splicing protein isoforms in the human heart

2021 ◽  
Vol 154 ◽  
pp. 92-96
Author(s):  
Yu Han ◽  
Silas D. Wood ◽  
Julianna M. Wright ◽  
Vishantie Dostal ◽  
Edward Lau ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Human Heart ◽  
Protein Isoforms ◽  
Targeted Proteomics

scholarly journals Integrative Visual Analysis of the Effects of Alternative Splicing on Protein Domain Interaction Networks

2008 ◽  
Vol 5 (2) ◽  
Author(s):  
Dorothea Emig ◽  
Melissa S. Cline ◽  
Karsten Klein ◽  
Anne Kunert ◽  
Petra Mutzel ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Protein Interactions ◽  
Visual Analysis ◽  
Protein Isoforms ◽  
Interaction Networks ◽  
Protein Domain ◽  
Domain Interaction ◽  
Exon Arrays ◽  
Exon Expression ◽  
Splicing Patterns

SummaryProteins and their interactions are essential for the functioning of all organisms and for understanding biological processes. Alternative splicing is an important molecular mechanism for increasing the protein diversity in eukaryotic cells. Splicing events that alter the protein structure and the domain composition can be responsible for the regulation of protein interactions and the functional diversity of different tissues. Discovering the occurrence of splicing events and studying protein isoforms have become feasible using Affymetrix Exon Arrays. Therefore, we have developed the versatile Cytoscape plugin DomainGraph that allows for the visual analysis of protein domain interaction networks and their integration with exon expression data. Protein domains affected by alternative splicing are highlighted and splicing patterns can be compared.

Sign in / Sign up

Export Citation Format

Share Document