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Human initiation factor eIF3 subunit b interacts with HCV IRES RNA through its N-terminal RNA recognition motif.

Research paper by Julien J Pérard, Rodolfo R Rasia, Jan J Medenbach, Isabel I Ayala, Jérôme J Boisbouvier, Emmanuel E Drouet, Florence F Baudin

Indexed on: 09 Dec '08Published on: 09 Dec '08Published in: FEBS Letters



Abstract

Many viral mRNAs contain a 5'-UTR RNA element called internal ribosome-entry site (IRES), which bypasses the requirement of some canonical initiation factors allowing cap-independent translation. The IRES of hepatitis-C virus drives translation by directly recruiting 40S ribosomal subunits and binds to eIF3 which plays a critical role in both cap-dependent and cap-independent translation. However, the molecular basis for eIF3 activity in either case remains enigmatic. Here we report that subunit b of the eIF3 complex directly binds to HCV IRES domain III via its N-terminal-RRM. Because eIF3b was previously shown to be involved in eIF3j binding, biological implications are discussed.