Poster abstracts

Poster number 68 submitted by Prashant Rajan

A thermodynamic study of HIV splicing factors

Prashant V. Rajan (Department of Chemistry and Biochemistry, Miami University), Blanton S. Tolbert, PhD (Department of Chemistry and Biochemistry, Miami University)

Abstract:
The alternative splicing pathway within the HIV-1 virus plays a key role in HIV replication and viral infectivity; however splicing mechanisms in HIV are poorly understood at the molecular level. In alternative splicing, the protein-coding exons of the viral pre-mRNA are isolated from the non-protein coding introns and then ligated in various permutations, thereby resulting in the full protein complement for the virus. Genome splicing in HIV is dynamically modulated by interactions between cis and trans regulatory elements; the trans factors belong to the host’s SR and hnRNP factors. The host factor hnRNP A1 negatively regulates ssA2, ssA3, and ssA7 by binding cis silencer elements that are embedded within regions containing higher-order RNA structure. Recently, we have solved the NMR structure of ESS3, which is located at ssA7. This structure revealed unique stereochemical and tertiary properties at the A1 binding site. Based on these results, we hypothesize that structural environment modulates hnRNP A1-ESS3 interactions, which in turn may affect splicing activity. As an initial step to test that concept, this study is focused on comparing binding affinities of hnRNP A1 to different ESS3 elements across different clades of HIV. Insights from this study will allow us to better understand the splicing mechanisms that underlie HIV replication.

Keywords: Splicing, HIV, RNA