title: Incorporation of chimeric gag protein into retroviral particles.
abstract: The product of the Rous sarcoma virus (RSV) gag gene, Pr76gag, is a polyprotein precursor which is cleaved by the viral protease to yield the major structural proteins of the virion during particle assembly in avian host cells. We have recently shown that myristylated forms of the RSV Gag protein can induce particle formation with very high efficiency when expressed in mammalian cells (J. W. Wills, R. C. Craven, and J. A. Achacoso, J. Virol. 63:4331-4343, 1989). We made use of this mammalian system to examine the abilities of foreign antigens to be incorporated into particles when fused directly to the myristylated Gag protein. Our initial experiments showed that removal of various portions of the viral protease located at the carboxy terminus of the RSV Gag protein did not disrupt particle formation. We therefore chose this region for coupling of iso-1-cytochrome c from Saccharomyces cerevisiae to Gag. This was accomplished by constructing an in-frame fusion of the CYC1 and gag coding sequences at a common restriction endonuclease site. Expression of the chimeric gene resulted in synthesis of the Gag-cytochrome fusion protein and its release into the cell culture medium. The chimeric particles were readily purified by simple centrifugation, and transmission electron microscopy of cells that produced them revealed a morphology similar to that of immature type C retrovirions.
authors.affiliation: Department of Biochemistry and Molecular Biology, Louisiana State University Medical Center-Shreveport 71130.
authors.forename: R A
authors.initials: RA
authors.lastname: Weldon
authors.forename: C R
authors.initials: CR
authors.lastname: Erdie
authors.forename: M G
authors.initials: MG
authors.lastname: Oliver
authors.forename: J W
authors.initials: JW
authors.lastname: Wills
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001358:Avian Sarcoma Viruses / Q000235:genetics* / Q000648:ultrastructure; D002460:Cell Line; D002678:Chimera; D002872:Chromosome Deletion; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts / Q000648:ultrastructure; D015683:Gene Products, gag / Q000235:genetics* / Q000302:isolation & purification; D015750:Genes, gag; D005822:Genetic Vectors; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification; D015183:Restriction Mapping; D014162:Transfection; D014422:Turkeys
chemical_list: D015683:Gene Products, gag; D011993:Recombinant Fusion Proteins