INTERACTION OF THE VIRAL PROTEIN GENOME LINKED OF TURNIP MOSAIC POTYVIRUS WITH THE TRANSLATIONAL EUKARYOTIC INITIATION-FACTOR (ISO) 4E OF ARABIDOPSIS-THALIANA USING THE YEAST 2-HYBRID SYSTEM

The yeast LexA interaction trap was used to screen a cDNA library from Arabidopsis thaliana in order to identify proteins that interact with the viral protein genome linked (VPg)-proteinase of turnip mosaic pot yvirus. The screen allowed the isolation of four candidate cDNA clones . Clones pHC4, pHC21, and pHC40 were partially sequenced but no homolo gies to known proteins were found. However, the amino acid sequence de duced from the complete nucleotide sequence of pSW56 revealed that it was the eukaryotic initiation factor (iso) 45 [elF(iso)4E]. Deletion a nalysis indicated that the VPg domain was involved in the interaction with the plant protein. Interaction between the viral protein and the cellular protein was confirmed by ELISA-based binding experiments. elF (iso)4E plays an essential role in the initiation of the translation o f capped mRNAs and its association with VPg would point to a role of t he viral protein in the translation of the virus. (C) 1997 Academic Pr ess.