title: Synthesis and processing of precursor polypeptides to murine mammary tumor virus structural proteins.
abstract: Biosynthesis of murine mammary tumor virus (MuMTV) proteins was studied in the chronically MuMTV-infected epithelial cell line MuMT-73 by using monospecific antisera to the major MuMTV core protein p27 and the major envelope glycoprotein gp47. In pulse-labeling experiments using [35S]methionine, monospecific antisera to p27 precipitated a 75,000-molecular-weight protein as the major intracellular component. Analysis of the same cellular extracts with monospecific antisera to gp47 revealed that the gp47 precursor was a 70,000-dalton protein. After chase periods, there was a loss of label from the precursors and a concomitant increase of labeled extracellular mature viral proteins. The glycoprotein precursor incorporated labeled glucosamine and seemed to be processed more rapidly than the p27 precursor. Considerable amounts of apparently nonvirion-associated gp47 and glycoprotein precursor could be detected in the extracellular culture fluid.
mesh_terms: D002460:Cell Line; D006023:Glycoproteins / Q000096:biosynthesis / Q000378:metabolism; D008324:Mammary Tumor Virus, Mouse / Q000378:metabolism*; D008970:Molecular Weight; D010452:Peptide Biosynthesis; D010455:Peptides / Q000378:metabolism; D011498:Protein Precursors / Q000096:biosynthesis* / Q000378:metabolism; D014764:Viral Proteins / Q000096:biosynthesis* / Q000378:metabolism
chemical_list: D006023:Glycoproteins; D010455:Peptides; D011498:Protein Precursors; D014764:Viral Proteins