Grant: $103,248 - National Institutes of Health - Sep. 18, 2009
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Award Description: The long range goal of this project remains to understand that role the polyadenylation plays in post-transcriptional regulation in prokaryotes. Although long considered to be a feature unique to eukaryotes, over the past 10 years it has been shown that polyadenylation is intimately involved in mRNA decay, RRNA processing, tRNA maturation, sRNA degradation, and overall RNA quality control in /Eschericha coli/. Of equal importance, it has now been demonstrated that polyadenylation, either by poly(A) polymerase type enzymes or polynucleotide phosphorylase (PNPase) is involved in the post-transcriptional modification of RNA in almost all prokaryotes. In addition, over the past few years it has been shown that eukaryotes contain a nuclear polyadenylation system that closely mimics the /E. coli/ system in that it targets defective Pol II transcripts for degradation. Thus /E. coli/ is an excellent prokaryotic model system for studying this complex system. Based on progress we have made since this grant (GM57220) was initially funded, we are in an excellent position to develop a much more sophisticated understanding of both the biochemical mechanism of polyadenylation and the roles it plays in mRNA decay, tRNA maturation, sRNA biogenesis and decay, and rRNA processing. The specific lines of experimentation proposed for the current project period includes: 1. Analyze the composition and function of the polyadenylation complex /in vivo/ and /in vitro/; 2. Determine the essential requirements for a Rho-independent transcript terminator to function as a polyadenylation signal; 3. Determine whether PAP I preferentially polyadenylates full-length or partially degraded transcripts; 4. Determine the role of polyadenylation in the maturation fo rRNAs and tRNAs; and 5. Analyze the interactions between poly (A) tails and the RNase E-based degradosome in the initiation of mRNA decay. We are actively pursuing all five of these areas of research. In addition, since this grant was last reviewed in June 2008, we have initiated a collaberation with Tom Silhavy at Princeton University. One of his graduate students, working on the response regualtory protein, SprE (RssA), made an observation that this protein might have an effect on the /in vivo/ levels of polyadenylation. Over the past few months we have shown that deletion of the SprE locus leads to a significant reduction in the intracellular level of polyadenylation and increased half-lives for a number of specific mRNAs. This exciting new finding suggests that there is another level of control over the polyadenylation pathway in /E. coli/. As such we plan to carry out some additional experiments to determine how the SprE proten functions in controlling intracellular levels of poly(A).
Project Description: As defined in the Award Description Field
Infrastructure Description: N/A
Jobs Summary: Not started (Total jobs reported: 0)
Project Status: Not Started
This award's data was last updated on Sep. 18, 2009. Help expand these official descriptions using the wiki below.