IDENTIFICATION OF A PROTEIN LINKED TO THE GENOMIC AND SUBGENOMIC MESSENGER-RNAS OF FELINE CALICIVIRUS AND ITS ROLE IN TRANSLATION

I-125 protein labelling of oligo(dT)-selected RNA from feline calicivi rus (FCV)-infected cells revealed that the genomic and 2.4 kb subgenom ic RNAs of FCV are linked to a 15 kDa protein (VPg). Proteinase K trea tment of FCV RNA, to remove VPg, led to a decrease in the translatabil ity of the RNA, but there was no obvious change in the site of RNA ini tiation. Addition of the cap analogue 7-methylGTP to in vitro translat ions had no effect on the translation of FCV RNA, suggesting that FCV RNA is translated by a cap-independent mechanism. Further evidence tha t FCV RNA is translated by an unusual mechanism was obtained by transl ating FCV RNA in vitro at a range of K+ concentrations. FCV RNA was ab le to direct translation at K+ concentrations at which cellular RNA tr anslation was inhibited.