MOUSE HEPATITIS-VIRUS GENE 5B PROTEIN IS A NEW VIRION ENVELOPE PROTEIN

Highly purified radiolabeled mouse hepatitis virus (MHV) A59 contained a previously overlooked protein which coelectrophoreses with the gene 5b product immunoprecipitated from infected cells. The gene 5b protei n is post-translationally acylated. Rabbit antibody raised against a r ecombinant gene 5b protein expressed in Escherichia coli neutralized v iral infectivity in the presence of complement, although not in the ab sence of complement. Immunofluorescent staining of MHV-infected cells with two anti-peptide antibodies revealed that the gene 5b product is membrane-associated and is transported to the cell surface, findings c onsistent with the prediction of a membrane-spanning segment in the ge ne 5b polypeptide. These results suggest strongly that the gene 5b pol ypeptide represents a new MHV virion envelope protein which is homolog ous to the TGEV ORF 4 and IBV 3c proteins. (C) 1994 Academic Press, In c.