Hepatitis C Virus Internal Ribosome Entry Site-mediated Translation Is Stimulated by Specific Interaction of Independent Regions of Human La Autoantigen

Pudi, Renuka and Abhiman, Saraswathi and Srinivasan, Narayanaswamy and Das, Saumitra (2003) Hepatitis C Virus Internal Ribosome Entry Site-mediated Translation Is Stimulated by Specific Interaction of Independent Regions of Human La Autoantigen. In: Journal of Biological Chemistry, 278 (14). pp. 12231-12240.

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Abstract

The human La autoantigen has been shown to interact with the internal ribosome entry site (IRES) of hepatitis C virus (HCV) in vitro. Using a yeast three-hybrid system, we demonstrated that, in addition to full-length La protein, both N- and C-terminal halves were able to interact with HCV IRES in vivo. The exogenous addition of purified full-length and truncated La proteins in rabbit reticulocyte lysate showed dose-dependent stimulation of HCV IRES-mediated translation. However, an additive effect was achieved adding the terminal halves together in the reaction, suggesting that both might play critical roles in achieving full stimulatory activity of the full-length La protein. Using computational analysis, three-dimensional structures of the RNA recognition motifs (RRM) of the La protein were independently modeled. Of the three putative RRMs, RRM2 was predicted to have a good binding pocket for the interaction with the HCV IRES around the GCAC motif near the initiator AUG and RRM3 binds perhaps in a different location. This observation was further investigated by the filter-binding and toe-printing assays. The results presented here strongly suggest that both the N- and C-terminal halves can interact independently with the HCV IRES and are involved in stimulating internal initiation of translation.

Item Type:	Journal Article
Publication:	Journal of Biological Chemistry
Publisher:	American Society for Biochemistry and Molecular Biology Inc.
Additional Information:	The copyright of this article belongs to The American Society for Biochemistry and Molecular Biology, Inc.
Keywords:	Viruses; RNA; Yeast
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	16 May 2007
Last Modified:	22 Feb 2012 07:26
URI:	http://eprints.iisc.ac.in/id/eprint/10947

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