title: [Effect of toyocamycin on the biosynthesis of viral glycoproteins in a cell line chronically infected with a murine retrovirus].
abstract: Toyocamycin (TMC), an adenosine analog has been previously reported to inhibit both number and infectivity of retrovirus particles released by chronically infected cells (Bonar et al., 1970; Riman, 1971; Mauchauffé et al., 1979). We have previously shown that loss of infectivity could result from the incorporation of TMC in place of adenosine in the genomic 35S RNA (Larsen et al., 1979). This phenomenon is likely to impair the structure of the viral genome in such a way that reverse transcriptase cannot properly copy the template. Another consequence of the Toyocamycin action on the retrovirus particles released by analog-treated cells was their reduced content in envelope glycoprotein or gp70 (Mathieu - Mahul et al., 1979). In order to find the origin of this defect, which could also explain the loss of infectivity, viral polypeptides present in the cytoplasm of Toyocamycin-treated cells were analyzed by immunoprecipitation with specific antisera. The results indicated a diminution of the biosynthesis of the envelope glycoprotein and other GAG gene-related polypeptides. However, the gpr85env precursor was normally synthesized and processed into its final products (gp70 + p15E), which accumulated in the cells. These result make it likely that Toyocamycin has no specific effect on the virus replicative process in chronically infected cells but acts by deteriorating cellular functions, which are necessary to virus assembly. Indeed, it was found that a membrane fraction corresponding to smooth endoplasmic reticulum and Golgi apparatus was severely reduced if not totally suppressed in TMC-treated cells.
mesh_terms: D000818:Animals; D002460:Cell Line; D005622:Friend murine leukemia virus / Q000378:metabolism*; D006023:Glycoproteins / Q000096:biosynthesis*; D008566:Membranes / Q000378:metabolism; D051379:Mice; D012263:Ribonucleosides / Q000494:pharmacology*; D014127:Toyocamycin / Q000494:pharmacology*; D014764:Viral Proteins / Q000096:biosynthesis*
chemical_list: D006023:Glycoproteins; D012263:Ribonucleosides; D014764:Viral Proteins; D014127:Toyocamycin
vernacular_title: Action de la toyocamycine sur la biosynthèse des glycoproéines virales dans une lignée chroniquement infectée par un rétrovirus murin.