Mapping Rna Protein Interactions In Saccharomyces Cerevisiae

We are on the threshold of a new era in our understanding of that fantastic feat of regulation at the core of life itself--gene expression. The rapid pace of new developments in genome-wide, high-throughput technologies has allowed us unprecedented access to observe multiple stages of the gene expression program for nearly the entire genome. This has revealed a widespread discordance between mRNA abundance and protein abundance for many genes whose expression changes in response to environmental stimuli, and a significant coordination of post-transcriptional regulation for specific sets of related mRNAs at the levels localization, translation, decay, and the noise in gene expression. Despite this evidence suggesting the existence of a coordinated regulatory framework that potentially affects the fate of every mRNA in the cell, our efforts to discern the underlying structure and regulatory themes are hindered by an incomplete understanding of RNA-protein interactions. To advance our comprehension of post-transcriptional regulation, we developed new tools to identify which proteins bind to RNA, which of those bind concurrently, which RNAs are bound by a given protein, and where each protein binds on each RNA. Using our proteomic tools we discovered hundreds unexpected RNA binding proteins, uncovered new RNA binding domains, identified widespread, concurrent binding with several RNA binding proteins, and inferred functional information from the simultaneous binding partners of several RNA binding proteins. We used our genomic, sequencing-based tools to systematically interrogate a large set of diverse RNA binding proteins and we discerned new themes from the resulting data. This revealed significant differences in function, localization, and regulation among the proteins encoded by the targets of a given RNA binding protein based on binding position. These results suggest that the functional consequences of the RBP-RNA interaction are determined not only by whether an mRNA is bound by an RBP but also by the position of the binding site within the mRNA and its relation to the other RBPs that bind the same mRNA. Overall, we found evidence of an extensive regulatory framework involving hundreds of RNA binding proteins, encompassing nearly the entire transcriptome, and extending our understanding of the RNA-protein interactions at the heart of post-transcriptional regulation.