Molecular Interactions in the Replication of Mouse Hepatitis Virus.

摘要

Functions of two structural proteins of mouse hepatitis virus (MHV) have been studied to elucidate their biological significance. Others have shown that the 180K E2 glycoprotein of MHV is found on virions partially cleaved into 90K polypeptides, and further cleavage of E2 with trypsin activates cell fusion in vitro. The cellular site of E2 cleavage and the role of cleavage in virus infectivity were investigated. A method for isolating intracellular virus (ICV) particles was developed. Radiolabeled ICV carried less E2-90 than did released virions. Monensin treatment slowed virus budding, inhibited cleavage of E2, and reduced the yield of infectious virus by one hundred-fold. Trypsin treatment of ICV or virus grown in the presence of monensin did not enhance virus infectivity. These results suggest that E2 is cleaved on virions after they are transported from the medial region of the Golgi, and that only a portion of E2-l80 must be cleaved to E2-90 to make virions infectious.