title: Maturation of mouse mammary tumor virus envelope protein is blocked by a specific point mutation.
abstract: Expression of a mouse mammary tumor virus (MMTV) envelope gene, ENV2, in COS-7 cells resulted in the synthesis of a precursor protein Pr74 that underwent complete proteolytic processing to the mature envelope species gp52 and gp33. In contrast, expression of a second MMTV envelope gene, ENV1, in COS-7 cells resulted in the synthesis of a precursor protein Pr74 that failed to undergo proteolytic processing to the mature products. Expression and sequencing of various chimeric ENV1/ENV2 genes determined that a single glycine-to-glutamic acid mutation at position 54 was responsible for the nonprocessable phenotype of ENV1-encoded Pr74. The significance of this point mutation in relation to the requirements for precursor protein folding and maturation are discussed.
authors.affiliation: Department of Pathology, University of Southern California Health Sciences Center, Los Angeles 90033.
authors.forename: R M
authors.initials: RM
authors.lastname: Bedgood
authors.forename: L D
authors.initials: LD
authors.lastname: Snider
authors.forename: M R
authors.initials: MR
authors.lastname: Stallcup
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D015752:Genes, env / Q000235:genetics*; D008324:Mammary Tumor Virus, Mouse / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D011498:Protein Precursors / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D014759:Viral Envelope Proteins / Q000378:metabolism*
chemical_list: D011498:Protein Precursors; D014759:Viral Envelope Proteins