BIOC 4403 Lecture Notes - Lecture 20: Spliceosome, Neural Development, Cd44
7 Mar 2016
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4403 - 20 alternative splicing ii: types of alternative pre-mrna splicing, exon skipping, alternative exon size, lntron retention, less frequent: Alternative polyadenylation: four mechanistic categories of altered gene function by splicing mutations, 1. Exon skipping whole exons are either skipped (i. e. left out) or spliced into mrna. Most common form of splicing in metazoans: 2. Alternative exon size: 3 lntron retention exons can also come in different sizes through using different splice sites to be spliced into the mrna-this makes exons either shorter or longer at either end. Second most common form of splicing in metazoans. within genomic dna and in unspliced pre- mrna exons are separated from each other by introns, and splicing usually joins the exons together. However, whole introns can sometimes be retained in mrnas ( i. e. remain unspliced ). Mutations can lead to a new alternative 5 splice site (5 ss) or 3 ss. Mutations can lead to suboptimal recognition of the 5 ss.
