CMMB 411 Lecture Notes - Lecture 37: Alternative Splicing, Rna Splicing, Sr Protein
23 Dec 2018
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Alternative splicing: multiple ways to splice an mrna. Alternative splicing usually changes the protein product. Alternative splicing is regulated and differs over time and among cell types. The central catalytic activity of splicing resides in snrnas rather than all the proteins. The proteins are thought to bring everything together in a proper way so the rns can form a structure that can splice. Types of alternative splicing: normal splicing, exon skipped (middle exon ignored), exon extended (cryptic 3" splice site used, instead of actual one), intron retained (not spliced), alternative exon (either exon spliced, not both) Correct splicing and alternative splicing is aided by sr proteins that bind to. The binding of sr proteins helps recruit spliceosomal components and enhances a splice site. There are also ise (intron splicing enhancers) and esss and isss (exon/intron splicing silencers) These signals give specificity information in addition to the splice site consensus sequences.
