title: Site-directed mutagenesis of the gag-myc gene of avian myelocytomatosis virus 29: biological activity and intracellular localization of structurally altered proteins.
abstract: Transfection of chicken embryo cells with pMC29, a plasmid vector containing the sequences for the acute transforming virus MC29, and a cloned transformation-defective helper virus, p delta Mst, resulted in morphological transformation, the synthesis of P110gag-myc (the product of the gag-myc oncogene), and the production of infectious virus. MC29 mutants bearing site-directed deletions within the gag-specific sequences or within the middle portion of the myc sequences efficiently induced transformation of chicken embryo cells in culture. However, variants containing deletions of sequences in the amino-terminal half or carboxy-terminal portion of the myc gene were defective for transformation. The gag-myc proteins encoded by these variants efficiently localized to the cell nucleus. Premature termination mutants were isolated which encoded gag-myc proteins lacking the carboxy-terminal 185 residues; these truncated proteins localized to both the nucleus and the cytoplasm. Deletion of as few as 11 residues within the middle of the myc-specific sequences (residues Ile-239 to Glu-249) significantly reduced the efficiency of chicken hematopoietic cell transformation.
mesh_terms: D000818:Animals; D001354:Avian Leukosis Virus / Q000235:genetics* / Q000502:physiology; D002467:Cell Nucleus / Q000032:analysis; D002472:Cell Transformation, Viral; D002642:Chick Embryo; D005347:Fibroblasts / Q000032:analysis; D015683:Gene Products, gag; D005814:Genes, Viral; D005821:Genetic Techniques; D005822:Genetic Vectors; D009856:Oncogene Proteins, Viral / Q000032:analysis / Q000235:genetics*; D009857:Oncogenes; D011994:Recombinant Proteins / Q000032:analysis / Q000235:genetics; D012191:Retroviridae Proteins / Q000032:analysis / Q000235:genetics*
chemical_list: D015683:Gene Products, gag; D009856:Oncogene Proteins, Viral; D011994:Recombinant Proteins; D012191:Retroviridae Proteins