Proteins of vesicular stomatitis virus: III. Intracellular synthesis and extracellular appearance of virus-specific proteins

Abstract

An examination of the kinetics of synthesis and release of virus-specific proteins from VSV-infected cells showed that the rate of virus protein synthesis was maximal about 4 hr post infection, a constant proportion of the newly synthesized protein being released from the cell at all times. Five virus-specific proteins VP1, VP2, VP3, VP4, and NS1 were identified in infected cells. The intracellular protein VP2 was shown to be distinct by its mobility on polyacrylamide gels from both the virion glycoprotein VP2 and the soluble antigen glycoprotein VP2a and may be a precursor to these proteins. Exposing cells to actinomycin D for 20 hr prior to infection showed that the relative rate of synthesis of NS1 was greatest in the first 2 hr of infection and decreased at later times. In contrast, the virion envelope proteins VP2 and VP4 formed an increasing proportion of virus protein synthesis with time. The result suggests that the protein NS1 may have an early intracellular function in replication. Pulse-chase experiments showed that the proteins VP1 and VP4 could be released from the cell soon after synthesis while newly synthesized VP2 and VP3 appeared in extracellular virus only after some delay.