3’ processing of mRNA is a critical step in gene expression and regulation. Although seemingly simple with two major steps (cleavage and polyadenylation), 3’ processing requires a large number of proteins to recognize sequence elements on the immature mRNA, bind to them in a sequence specific manner, and then recruit additional proteins in order for the two reactions to occur. Improperly processed transcripts are retained in the nucleus and degraded. Evidence has been shown that transcription, processing and nuclear export of mRNA are not individual and separate events, but rather they occur cotranscriptionally. My goal is to characterize how these protein-protein/protein-RNA interactions facilitate the proper processing and export of mRNA using biochemical, spectroscopic and crystallographic techniques.
Figure 1. Diagram showing the multiple subunit complexes that form on the 3’ end of mammalian mRNAs during processing. (Danckwardt et al, 2008)
Npl3
Npl3 is a SR protein found in yeast, and is involved in RNA transport and pre-mRNA processing. Our group previously (Deka et al, 2008) solved the structure of Npl3’s two RNA recognition motifs (RRM) by NMR. I am currently working on expanding the work by solving the structure of Npl3 (121-280) complexed with a G-U rich sequence of RNA which we found that Npl3 binds tightly to.