Analysis of the in Vitro Cleavage Products of the Tomato Black Ring Virus RNA-1-encoded 250K Polyprotein

Tomato black ring virus RNA-1 was translated in a rabbit reticulocyte lysate. The primary translation product of M r 250K, which corresponds to its whole coding capacity, was synthesized within 45 min and, during further incubation in the translation medium, was proteolytically processed. Essentially, four cleavage products (P190, P120, P60 and P50) were detected and located within P250 by pulse-chase and immunoprecipitation experiments. P190 is an intermediate cleavage product which is further cleaved to form P60 and P120. P120, which contains the region that has been assigned to the virus protease and the virus polymerase, was not further cleaved in vitro.