What is alternative splicing and why is it important?
What is alternative splicing and why is it important?
Alternative splicing of RNA is a crucial process for changing the genomic instructions into functional proteins. It plays a critical role in the regulation of gene expression and protein diversity in a variety of eukaryotes. In humans, approximately 95% of multi-exon genes undergo alternative splicing.
What is the difference between splicing and alternative splicing?
Constitutive splicing is the process of intron removal and exon ligation of the majority of the exons in the order in which they appear in a gene. Alternative splicing is a deviation from this preferred sequence where certain exons are skipped resulting in various forms of mature mRNA.
What controls alternative splicing?
Splicing is regulated by trans-acting proteins (repressors and activators) and corresponding cis-acting regulatory sites (silencers and enhancers) on the pre-mRNA. Together, these elements form a “splicing code” that governs how splicing will occur under different cellular conditions.
What is an example of alternative splicing?
Alternative splicing is a powerful means of controlling gene expression and increasing protein diversity. The best example is the Drosophila Down syndrome cell adhesion molecule (Dscam) gene, which can generate 38,016 isoforms by the alternative splicing of 95 variable exons.
What diseases are caused by alternative splicing?
Well-studied diseases caused by changes in splice site selection include thalassemias [97] and Familial dysautonomia (FD).
What is the main purpose of alternative splicing?
The overall function of alternative splicing is to increase the diversity of the mRNA expressed from the genome. Due to the combinatorial control mechanisms that regulate alternative exon recognition, splicing programs coordinate the generation of mRNA isoforms from multiple genes.
Is RNA splicing and alternative splicing the same?
The main difference between RNA splicing and alternative splicing is that the RNA splicing is the process of splicing the exons of the primary transcript of mRNA whereas the alternative splicing is the process of producing differential combinations of exons of the same gene.
What is the benefit of alternative splicing?
What affects alternative splicing?
Splicing of individual pre-mRNAs is frequently controlled by combinatorial or competitive effects of both activators and inhibitors. The final decision of whether an alternative exon is included is determined by the concentration or activity of each type of regulator, often by SR proteins and hnRNPs72–74.
Why does alternative splicing happen?
Alternative splicing occurs after a primary mRNA is created from the DNA. The primary mRNA has various regions, called introns and exons. These regions are mixed together, and the introns must be removed to create a functional protein. The spliceosome is specially equipped to remove the introns.
What happens during alternative splicing?
Therefore, alternative splicing, a type of post-transcriptional modification, is the process by which exons or portions of exons or non-coding regions within a pre-mRNA transcript are differentially joined or skipped, resulting in multiple protein isoforms being encoded by a single gene.
Can alternative splicing cause mutations?
Changes in alternative splicing can be the cause or consequence of human diseases. There are only a few reports of mutations in core elements of the splicing machinery that result in human diseases.
Which is an alternative 5’splice junction on GitHub?
Alternative 5′ splice site (A5SS): An alternative 5′ splice junction (donor site) is used that changes the 3′ boundary of the upstream exon. Alternative 3′ splice site (A3SS): An alternative 3′ splice junction (acceptor site) is used that changes the 5′ boundary of the downstream exon.
Which is the Alternative 3’splice site in Alexa?
Alternative 3′ splice site (A3SS): An alternative 3′ splice junction (acceptor site) is used that changes the 5′ boundary of the downstream exon. Retained intron (RI): A sequence may be spliced out as an intron or retained, and there are no flanking introns. ALEXA-Seq – alternative expression analysis by massively parallel sequencing.
How are alternative exons identified in a splice pair?
(4) To ensure reliable junction peptides can be identified that span constitutive and alternative exons, we stitch both translated slices in a splice pair (each containing one upstream exon, the alternative exons, and one downstream exon) back-to-back to the full-length canonical sequences from SwissProt through a 10-amino-acid (aa) overhang.
How are junctions used to detect alternative splicing?
The junction information is used to rank the identified exons from strongly confident to less confident candidates for alternative splicing. The design of junctions was also discussed to highlight the complexity of exon-exon and exon-junction interactions.