Role of Ser-Arg Proteins in the Regulation of RNA Processing
Annual summary rept. 1 Sep 1998-31 Aug 1999
TORONTO UNIV (ONTARIO)
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We have identified a complex SR-related matrix proteins of 16OkDa and 3OOkDa SRm16O3OO that functions in splicing by promoting critical interactions between splicing factors bound to pre-mRNA, including snRNPs and SR family proteins Blencowe et al., 1998 Eldridge et al., 1999. During the past year, we have investigated the functions of the SRm16O3OO subunits. Surprisingly, specific depletion of SRm3O0 does not prevent the splicing of pre-mRNAs shown previously to require SRm160300. Addition of recombinant SRm160 alone to SRm16O30O-depleted reactions specifically activates splicing. The results indicate that SRm160 is the critical component of the SRm16O3OO coactivator in the splicing of SRm16O3OO dependent pre-mRNAs. This work paves the way for a more detailed investigation of interactions involving the SRm16O3O0 splicing coactivator that are important for constitutive and regulated pre-mRNA splicing. The carboxyl terminal domain CTD of the largest subunit of RNA polymerase II is important for the efficient processing of pre-mRNA- it promotes 5 end capping, splicing and polyadenylation. In order to identify factors that communicate between the transcription and the RNA processing machineries, we have used affinity chromatography to purify proteins that specifically bind to the CTD.
- Medicine and Medical Research