Spliceosome assembly pathways for different types of alternative splicing converge during commitment to splice site pairing in the A complex.

ABSTRACT: Differential splice site pairing establishes alternative splicing patterns resulting in the generation of multiple mRNA isoforms. This process is carried out by the spliceosome, which is activated by a series of sequential structural rearrangements of its five core snRNPs. To determine when splice sites become functionally paired, we carried out a series of kinetic trap experiments using pre-mRNAs that undergo alternative 5' splice site selection or alternative exon inclusion. We show that commitment to splice site pairing in both cases occurs in the A complex, which is characterized by the ATP-dependent association of the U2 snRNP with the branch point. Interestingly, the timing of splice site pairing is independent of the intron or exon definition modes of splice site recognition. Using

SUBMITTER: Kotlajich MV 

PROVIDER: S-EPMC2643811 | biostudies-literature | 2009 Feb

REPOSITORIES: biostudies-literature