Gag-mos Polyproteins encoded by variants of the Moloney strain of mouse sarcoma virus.

Abstract

Two revertants of ts110 Moloney murine sarcoma virus (MuSV) with wild-type MuSV phenotype were examined for the presence of mos gene products, ts110 MuSV has a temperature-sensitive defect in a function required to maintain the transformed phenotype. The nonproducer 6m2 cell clone transformed by ts110 produces an 85,000-Da gag-mos protein (P85gag-mos) and a 58,000-Da gag protein (P58gag). A spontaneous revertant (clone 54-5A4) of the 6m2 cell clone produces a 100,000-Da protein (P100) recognized by antisera raised against murine leukemia virus p15, p12, and p30 but lacks determinants of p10, reverse transcriptase, and gp70. P100 was specifically recognized by antisera (anti-C3) prepared against a synthetic peptide representing the predicted C-terminal 12 amino acids of Moloney MuSV v-mos gene. Normal sera or anti-C3 blocked with excess synthetic peptide did not recognize P100. Thus, P100 is a product of the gag and mos genes. P100 was found to be phosphorylated. A second wild-type revertant (clone 204-3) was obtained by superinfection of ts110 nonproducer cells with Simian sarcoma associated virus (SSAV); it was also found to contain a phosphorylated P100gag-mos protein. The 204-3 cell clone also contained two gag polyproteins (Pr60gag and Pr55gag) of the size and antigenic properties of those found in SSAV-infected cells. These results provide two examples of P100 gag-mos proteins both derived from the P85gag-mos producing 6m2 cell clone. The P100 gag-mos polyproteins are made in amounts that are easily detected by radiolabeling experiments using [3H]leucine. The intracellular viral RNAs present in 6m2 cells and the two revertant clones were also examined. All three cell clones contained a 4.0 kb RNA hybridizing to v-mos sequences but only the 6m2 clone contained a 3.5 kb mos-containing RNA. Our findings indicate that the 3.5 kb RNA codes for P85gag-mos in cell-free translation experiments (Junghans et al., 1982, J. Mol. Biol. 161, 229). These findings as they relate to the mechanism that produces P100gag-mos instead of P85gag-mos are discussed.

• Authors: L H Stanker, J P Horn, G E Gallick, W S Kloetzer, E C Murphy Jr, D G Blair, R B Arlinghaus
• Journal: Virology (Virology) Vol. 126 Issue 1 Pg. 336-47 (Apr 15 1983) ISSN: 0042-6822 [Print] United States
• PMID: 6302990 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Phosphoproteins
• RNA, Viral
• Viral Proteins

Topics

• Animals
• Cell Line
• Cell Transformation, Neoplastic
• Cell Transformation, Viral
• Genes, Viral
• Mutation
• Oncogenes
• Phosphoproteins (biosynthesis)
• RNA, Viral (genetics)
• Rats
• Sarcoma Viruses, Murine (genetics, metabolism)
• Temperature
• Viral Proteins (biosynthesis, genetics)