Poster abstracts

Poster number 129 submitted by Michele Tolbert

hnRNP A1 Interacts with Conserved IRES Elements in Enterovirus 71

Michele Tolbert (Department of Chemistry, Case Western Reserve University), Jeffrey D. Levengood (Department of Chemistry, Case Western Reserve University), Mei-Ling Li (Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School), Blanton S. Tolbert (Department of Chemistry, Case Western Reserve University)

Abstract:
Recently named one of the top five emerging pathogens by the CDC, Enterovirus 71 is a positive single stranded RNA virus belonging to Picornaviridae. Due to the lack of a 5’ cap, EV71 utilizes an Internal Ribosome Entry Site (IRES) to regulate and promote the translation of viral proteins required for viral replication. A key ITAF involved in this Protein:RNA interaction is human hnRNP A1 which upon infection translocates from the nucleus to the cytoplasm to interact with Stem Loop II (SLII) and Stem Loop VI (SLVI). Little is known on how hnRNP A1 interacts with these two independently folding stem loops; we posit that RNA structure, as well as sequence, influences this Protein:RNA interaction. To characterize this interaction a series of bioinformatics, biophysical and virological techniques were utilized. We show that: (1) a high degree of secondary and sequence conservation is present within the IRES; (2) hnRNP A1 interacts biphasically with SLII at two distinct sites, a lower bulge with a conserved UAG motif and an upper hairpin containing a conserved CCA nucleotide motif and, (3) mutation of the UAG binding site in vivo leads to a significant reduction in viral translation and replication. To better elucidate this interaction a preliminary high resolution model of SLII was determined. Delineation of this interaction may pave the way for novel anti-viral therapies and treatments.

Keywords: IRES, hnRNP A1, ProteinRNA Interactions