The cauliflower mosaic virus translational transactivator interacts with the 60S ribosomal subunit protein L18 of Arabidopsis thaliana

The cauliflower mosaic virus (CaMV) open reading frame VI product (P6) is i nvolved in several aspects of the infectious cycle. P6 specifically control s the synthesis of other CaMV proteins by transactivating their expression from the polycistronic 35S RNA. By far-Western assays, we have demonstrated that P6 interacts with proteins from both healthy and Ca MV-infected leave s of Arabidopsis thaliana. These proteins are found in ribosome-enriched ex tracts, suggesting that they participate in the translation process. One of these proteins, identified by microsequencing, corresponds to the 60S ribo somal subunit protein L18 (RPL18). Its cDNA was cloned and expressed in Esc herichia coli, and the resulting RPL18 protein was shown to interact with t he minimal region required for translational transactivation, designated th e miniTAV domain of P6. (C) 2000 Academic Press.