Poster abstracts

Poster number 19 submitted by Joel Caporoso

Integrated techniques for the structure determination and RNA binding properties of SHARP

Joel Caporoso (Chemistry, The University of Akron), Caroline Davis (Chemistry, The University of Akron), Stephanie Bilinovich (Pathology, University of North Carolina), Louis Ray, Shaun Christie (Chemistry, The University of Akron), Sumirtha Balaratnam, Soumitra Basu (Chemistry, Kent State University), Thomas Leeper (Chemistry, The University of Akron)

Abstract:
SMRT/HDAC1 Associated Repressor Protein (SHARP) is a multi-domain protein that is involved in multipletranscription regulatory pathways. Four RNA Recognition Motifs (RRMs), that are found near the N-terminus of the protein, are believed to mediate its epigenetic action. Previous data has suggested that SHARP is involved in interacting and regulating the activity of the Steroid Receptor Activator RNA (SRA) through the use of these RRMs. Steroid Receptor Activator RNA (SRA) is a long, noncoding RNA (lncRNA) transcript that also encodes for the biosynthesis of another protein, SRA1p. lncRNAs typically do not participate in translation to make protein, but instead regulate gene expression by interacting with RNA-binding proteins, becoming coactivators for transcription factors, and repressing promoters. SRA, in particular, has been proposed to be involved in multiple complexes that regulate the transcription of nuclear steroid receptors. SHARP has the capability to repress the activity of SRA RNA through complex formation by direct interaction with its RRMs. Chemical shift perturbation studies via 15N heteronuclear single quantum correlation (HSQC) of SHARP and SRA RNA will be presented and indicate that there is a direct interaction between the two species. A preliminary nuclear magnetic resonance (NMR) structural model of a SHARP RRM with the likely binding pocket for the RNA will be discussed. Due to the size restraints of the ribonucleoprotein complexes, other techniques such as Small Angle X-ray Scattering (SAXS) and Paramagnetic Relaxation Enhancement (PRE) will be combined with traditional NMR data to examine the interactions. These and other biochemical data indicate that SHARP RRM 2 may be involved in structural remodeling of the STR7 loop of SRA.

Keywords: SHARP, SRA, NMR