Identification of host-cellular proteins binding to the 3’-end of murine norovirus RNA genome negative strand

Tuesday, October 09, 2012 — Poster Session I
1:00 p.m. – 3:00 p.m	Natcher Conference Center, Building 45	NIAID	VIROL-14

Authors

• C Sandoval-Jaime
• A Afiadata
• G.I. Parra
• E. J. Abente
• K. Bok
• R. Dexter
• K.Y. Green
• S.V. Sosnovtsev

Abstract

Murine norovirus (MNV) is the only norovirus in the Caliciviridae that replicates in cell culture, which has made it an important model system in the study of norovirus translation and replication. During the replication cycle of noroviruses, a negative-sense (-) RNA genome replicative intermediate is synthesized. Synthesis of this (-) RNA intermediate drives transcription of the (+) RNA progeny. The relative abundance of (+) RNA over (-) RNA during calicivirus replication suggests a comparatively more efficient transcription strategy of (-) RNA. In order to identify proteins associated with the 3’-end of the MNV negative strand, pull-down and cross-linking assays were performed using RNA transcripts corresponding to 78 nt of the MNV (-) RNA 3’-end. Two cellular proteins were isolated and identified through mass spectrometry as PTB and HnRNPU. Confocal microscopy of MNV-infected RAW264.7 cells confirmed co-localization of these proteins with components of the replication complex. This is the first report of HnRNPU as a calicivirus RNA binding protein. This is the first identification of PTB as a protein interacting with a calicivirus negative sense RNA. A better understanding of the (-) RNA transcription mechanism offers new possible antiviral targets, with potential applications for the human noroviruses associated with acute gastroenteritis.

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