Question

What is alternate (differential) splicing? How do specific splicing factors regulate alternate (differential) splicing?

Answer 1

Alternative or differential splicing is the regulatory mechanism of gene expression that results in functional proteins from genomic instructions.Many exons are skipped resulting in different forms of mature mRNA and Single gene codes for multiple proteins .

For example : In drosophila ,the Dscam gene contains 116 exons and many exons are skipped , retaining 17 exons in final mRNA and able to produce more number of different proteins.( Approximately 30,000). Alternative splicing increases the variation of mRNA expressed from genome .

Specific splicing factors regulate alternative splicing by turning on the splicing sites whenever it needs so that proteins to be expressed will bind to pre mRNA near that site .

SR proteins ( serine arginine rich proteins) regulate alternative splicing .Those with RS domain will recruit splicing machinery and activate specific splicing sites and those without RS domain will not recruit splicing machinery and repress specific splicing sites.