Detection of a transforming gene product in cells transformed by Moloney murine sarcoma virus.
We identified, in cells transformed by Moloney murine sarcoma virus (M-MuSV clone 124), a protein encoded by the M-MuSV transforming gene, v-mos. An antiserum against a synthetic peptide corresponding to the C terminus of a protein predicted from the v-mos nucleotide sequence specifically recognizes a protein doublet of approximately 37,000 daltons from 35S-methionine-labeled M-MuSV 124-transformed producer cells. By peptide mapping, this protein is almost identical to the 37 kd in vitro translation product from the M-MuSV v-mos gene. Immunoprecipitates from 32P-labeled cells contain a single v-mos-specific phosphoprotein, which has at least six sites of phosphorylation containing phosphoserine. Pulse-chase experiments show that the lower band in the 35S-methionine-labeled doublet is the primary translation product, which is modified, probably by phosphorylation, to yield the upper band. A similar mos protein is immunoprecipitated from HT1-MuSV-transformed cells, but not from uninfected NIH/3T3 cells. These mos proteins are present at very low levels in transformed cell lines. Cells acutely infected with M-MuSV 124, however, transiently contain much higher levels of the mos protein. These high levels coincide with extensive cell mortality.
D000818:Animals; D002472:Cell Transformation, Viral; D002478:Cells, Cultured; D005347:Fibroblasts / Q000378:metabolism; D051379:Mice; D008979:Moloney murine leukemia virus / Q000378:metabolism*; D010750:Phosphoproteins / Q000096:biosynthesis; D010766:Phosphorylation; D011498:Protein Precursors / Q000378:metabolism; D009053:Sarcoma Viruses, Murine / Q000378:metabolism*; D012694:Serine / Q000378:metabolism; D014764:Viral Proteins / Q000096:biosynthesis* / Q000378:metabolism
D010750:Phosphoproteins; D011498:Protein Precursors; D014764:Viral Proteins; D012694:Serine