Reovirus transcriptase activation in vitro: involvement of an endogenous uncoating activity in the second stage of the process.

Abstract

Uncoating of purified reovirions and activation of the endogenous transcriptase by in vitro digestion with chymotrypsin has been resolved into two mechanistically-distinct steps. The first step, mediated by chymotrypsin, converts virions into intermediate subviral particles (ISVP). The second step, which is not dependent on additional chymotryptic digestion, results in conversion of ISVP to cores and in transcriptase activation. The results suggest that reovirions contain a specialized mechanism which responds to specific stimuli from the microenvironment around the virion for activation of the endogenous transcriptase.