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Tyrosine 66 of Pepper vein banding virus genome-linked protein is uridylylated by RNA-dependent RNA polymerase

Anindya, Roy and Chittori, Sagar and Savithri, HS (2005) Tyrosine 66 of Pepper vein banding virus genome-linked protein is uridylylated by RNA-dependent RNA polymerase. In: Virology, 336 (2). pp. 154-162.


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Pepper vein banding virus (PVBV), a member of the genus potyvirus, is a single-stranded positive-sense RNA virus and it primarily infects plants of the family Solanaceae. Genome organization and gene expression strategy of the polyviruses are similar to the picomaviruses, although they infect widely different hosts and have distinctly different morphologies. The genomic RNA of PVBV has a viralgenome-linked protein (VPg) at the 5'-terminus and a poly(A) tail atthe 3'-terminus. In order to establish the role of VPg in the initiation of replication of the virus, recombinant PVBV NIb and VPg were over-expressed in Escherichia coli and purified under non-denaturing conditions. PVBV NIb was found to be active as polymerase and it could uridylylate the VPg in a template independent manner. N- and C-terminal deletion analysis of VPg revealed that N-terminal 21 and C-terminal 92 residues of PVBV VPg are dispensable for in vitro uridylylation. The amino acid residue uridylylated by PVBVNIb was identified to be Tyr 66 by site-directed mutagenesis. It is possible that in potyviruses, replication begins with uridylylation of VPg which acts as primer for progeny RNA synthesis.

Item Type: Journal Article
Publication: Virology
Publisher: Academic Press Inc Elsevier Science
Additional Information: Copyright for this article belongs to Elsevier.
Keywords: Potyvirus;VPg;NIb;Uridylylation;Replication
Department/Centre: Division of Biological Sciences > Biochemistry
Date Deposited: 05 Jul 2005
Last Modified: 19 Sep 2010 04:19
URI: http://eprints.iisc.ac.in/id/eprint/3314

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