2012 Fiscal Year Final Research Report

Development of the virus vaccine by the elucidation of the virulence of a plant virus

Research Project

Project/Area Number	23658042
Research Category	Grant-in-Aid for Challenging Exploratory Research
Allocation Type	Multi-year Fund
Research Field	Plant pathology
Research Institution	St. Marianna University School of Medicine
Principal Investigator	MIYOSHI Hiroshi 聖マリアンナ医科大学, 医学部, 講師 (80322519)
Co-Investigator(Kenkyū-buntansha)	TOMOO Koji 大阪薬科大学, 薬学部, 准教授 (70257898)
Project Period (FY)	2011 – 2012
Keywords	感染 / 増殖
Research Abstract	To elucidate the mechanism of RNA depurination, and to understand how PAP recognizes and targets various RNAs, the interactions between PAP and Turnip mosaic virus genome linked protein (VPg) were investigated. VPg can function as a cap analog in cap-independent translation, and potentially target PAP to uncapped IRES-containing RNA. In this work, fluorescence spectroscopy and HPLC techniques were used to quantitatively describe PAP depurination activity and PAP-VPg interactions. PAP binds to VPg with high affinity (29.5 nM); the reaction is enthalpically driven and entropically favored. Further, VPg is a potent inhibitor of PAP depurination of RNA in wheat germ lysate, and competes with structured RNA derived from tobacco etch virus (TEV) for PAP binding. VPg may confer an evolutionary advantage by suppressing one of the plant defense mechanisms, and also suggests the possible use of this protein against the cytotoxic activity of RIPs.