title: Transfer and expression of the bacterial NPT-II gene in chick embryos using a Schmidt-Ruppin retrovirus vector.
abstract: In an effort to introduce foreign genes into chickens, the bacterial neomycin phosphotransferase (NPT-II) gene was cloned into an infectious avian retroviral vector derived from the Schmidt-Ruppin A strain of RSV. The NPT-II gene was stable in the vector during passage in vitro and infected cells were resistant to G418. Fertilized chicken embryos were inoculated with the recombinant virus on day 0 and screened on day 20 for the NPT-II gene in blood cell DNA. Approximately 12% of the embryos were positive for the NPT-II gene. Screening of DNA from the brain, muscle, liver and foot of the positive embryos indicated that the NPT-II gene copy number could vary in a single embryo. However, some embryos had nearly equal NPT-II copy number in each tissue examined. To determine the expression of the bacterial gene, tissue extracts from the positive embryos were assayed for NPT-II activity. The results indicated that NPT-II activity varied depending on the tissue, with activity being highest in muscle and foot regardless of NPT-II gene copy number.
authors.affiliation: Monsanto Company, St Louis, MO 63198.
authors.forename: P J
authors.initials: PJ
authors.lastname: Hippenmeyer
authors.forename: G G
authors.initials: GG
authors.lastname: Krivi
authors.forename: M K
authors.initials: MK
authors.lastname: Highkin
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001358:Avian Sarcoma Viruses / Q000235:genetics*; D002642:Chick Embryo; D004274:DNA, Recombinant; D005786:Gene Expression Regulation; D005796:Genes; D005822:Genetic Vectors; D019868:Kanamycin Kinase; D010770:Phosphotransferases / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D014018:Tissue Distribution; D014158:Transcription, Genetic
chemical_list: D004274:DNA, Recombinant; D012333:RNA, Messenger; D010770:Phosphotransferases; D019868:Kanamycin Kinase