title: FBR murine osteosarcoma virus. I. Molecular analysis and characterization of a 75,000-Da gag-fos fusion product.
abstract: The FBR murine osteosarcoma virus complex induces bone tumors with a similar latency and pathology to those induced by the FBJ virus complex. FBR murine sarcoma virus ( FBR -MSV) has been isolated from its helper virus(es) by the establishment of transformed nonproducer cells. These cells were found to express a 75,000-Da protein (P75) which was antigenically related to the p55 oncogene product of the FBJ murine osteosarcoma virus ( FBJ -MSV). P75 also contained antigenic determinants of murine leukemia virus (MLV) gag gene p15, p12, and p30 proteins, and is therefore a gag- fos fusion protein ( P75gag - fos ). P75gag - fos is a phosphoprotein and is found primarily in the nucleus. Only a single species of RNA, of 3.3 kb, was identified in FBR -MSV-transformed nonproducer cells using both fos and MLV probes, which suggested that P75gag - fos was expressed from genome-sized RNA. Chromosomal DNA from one nonproducer cell line was found to contain a single EcoRI restriction fragment of 12 kb pairs (kbp) which encompassed the FBR -MSV provirus. This DNA fragment was molecularly cloned into bacteriophage Charon 30 (lambda FBR -1), and a 7.5-kbp HindIII restriction fragment containing the entire provirus was subsequently subcloned into pBR322 ( pFBR -1). DNA from pFBR -1 was capable of inducing morphological transformation of mouse and rat fibroblasts in tissue culture. In addition, transfected cells expressed the FBR -MSV P75gag - fos protein.
mesh_terms: D000818:Animals; D001859:Bone Neoplasms / Q000382:microbiology; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D003001:Cloning, Molecular; D004247:DNA / Q000302:isolation & purification; D004274:DNA, Recombinant / Q000378:metabolism; D015683:Gene Products, gag; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D012516:Osteosarcoma / Q000382:microbiology; D012313:RNA / Q000302:isolation & purification; D051381:Rats; D009053:Sarcoma Viruses, Murine / Q000235:genetics*; D014764:Viral Proteins / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D004274:DNA, Recombinant; D015683:Gene Products, gag; D014764:Viral Proteins; D012313:RNA; D004247:DNA