Poster abstracts

Poster number 70 submitted by Carrie Rollins

A Structural and Thermodynamic Study of Alternative Splicing of the HIV Genome

Carrie Rollins (Department of Chemistry and Biochemistry, Miami University), Jeffrey Levengood (Department of Chemistry and Biochemistry, Miami University), Clay Mishler (Department of Chemistry and Biochemistry, Miami University), Nitika Dewan (Department of Chemistry and Biochemistry, Miami University), Grace Miner (Department of Chemistry and Biochemistry, Miami University)

Abstract:
Despite advances in identifying splicing regulatory sequences in the HIV genome, the mechanism of alternative splicing has not been well defined on the molecular level. Splicing plays a critical role in the lifecycle of the virus, transforming one strand of pre-mRNA into over forty different mRNA constructs. Various combinations of acceptor and donor splice sites function to accomplish such variability, but how each splice site is utilized in competition with additional splice sites is not well understood. Host proteins such as heterogeneous ribonucleoprotein A1 (hnRNP A1) are known to downregulate splicing by binding to highly conserved acceptor splice sites A2, A3, and A7 and blocking spliceosome assembly. The protein-RNA interaction displays different levels of affinity with each acceptor site, suggesting that the structural environment may modulate complex stability. High-resolution structural information provides the foundation to define a splicing mechanism. The focus of this study is to elucidate the structures of SL^ISS and SL^ESS3 of splice site A7 as well as of SL^ESSV of splice site A2 using multidimensional NMR experiments. In addition we will define the mechanism of interaction these RNAs will make with the UP1 domain of hnRNP A1. Electromobility shift assays and isothermal titration calorimetry provide additional insight of the interaction to further understand this structure/function relationship.

Keywords: Alternative Splicing, HIV