RRM
2007 Rustbelt RNA Meeting
RRM
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Poster abstracts
Abstract:
The G patch is a conserved motif composed of about 40 amino acids that is present in a number of RNA binding proteins. I identified five G annotated patch proteins in Saccharomyces cerevisiae, namely, Spp2p, Spp382p, Sqs1p, Pxr1p and the uncharacterized ORF YLR271w. Of these, Spp2p and Spp382p interact with the splicing-associated DEAD/H box proteins Prp2p and Prp43p respectively. The published data are consistent with Spp2p and Spp282p acting as recruitment factors or activators of Prp2p and Prp43p, respectively. Pxr1p has been implicated in rRNA and snoRNA processing. The function(s) of the remaining two G patch proteins Sqs1p and Ylr271wp is unknown although neither is essential for cell viability. To begin my investigation of function, I compared the growth and splicing in yeast that overexpress each of the G-patch proteins. Our data reveal that overexpression of three (SPP382,SQS1 and PXR1) of the five G-patch proteins impair yeast growth at 30C. Overexpression of (at least) (SPP382,SQS1 and YLR271w impairs mRNA processing of intron-bearing transcripts, possibly through inhibition of one of the DExD/H-box proteins. No splicing defect was found in yeast deleted for either SQS1 or YLR271w.
Since Prp43p (the Spp382p–associated protein) is required for ribosome biogenesis as well as splicing, I also investigated the impact of overexpression of each factor on the Prp43-dependent cleavage of the 35S rRNA. While no clear inhibition was observed, we do see suppression of a spp382 (splicing factor) mutant when the ribosome biogenesis factor, Pxr1p is overexpressed. These and related observations are used to support a model for selective partitioning of Prp43p function in the nucleolus and nucleoplasm through association with alternative G-patch targeting factors.
Keywords: splicing, G-patch, Saccharomyces cerevisiae
