Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/6/2003
Publication Date: 7/31/2003
Citation: Zhang, H., Bacon, L.D., Kulkarni, G. 2003. Re-establishment of a transgenic chicken line 0-ALV6 at the Avian Disease and Oncology Laboratory [abstract]. Poultry Science Association. 82(1):49.
Technical Abstract: The first transgenic chicken line, 0.ALV6, was produced at the Avian Disease and Oncology Laboratory (ADOL) in 1989. Blastoderms of fertile freshly laid line 0 eggs were injected with the long terminal repeats of the endogenous Rous-associated virus (RAV-0) and the envelope gene (env) of a subgroup A avian sarcoma virus. The biological importance of the line 0.ALV6 is that it represents the first example of pathogen derived resistance in any animal created by transgenic techniques. The presence and expression of the env gene results in the absence of tumor development and mortality when line 0.ALV6 chickens are infected with subgroup A avian leukosis virus (ALV), in contrast to line 0 chickens. Line 0.ALV6 embryo cells are only resistant to subgroup A and E ALV. In 1998, during a change in farm management, line 0.ALV6 was not reproduced. In 1999, only two hens with limited egg production existed. To retain the line it was necessary to mate a 0.ALV6 homozygous male to line 0 hens. In 2000, the old ALV6 homozygous male was mated to ALV6 heterozygous hens to produce males. In 2001, four sires known to be ALV6 homozygous or heterozygous were mated to line 0 hens to produce 110 chicks. These chicks' DNA was analyzed using Southern blot analysis with a U3N probe developed at ADOL. In 2002, the adult ALV6 heterozygous hens were mated to an ALV6 homozygous male. To identify ALV6 homozygotes, the adult offspring were progeny tested by matings to line 0, and the test chicks' DNA was analyzed by a recently reported PCR-based procedure to identify the inserted proviral DNA. The PCR based test improved the efficiency and reduced the cost of identifying ALV6 homozygotes without compromising accuracy. In 2003, 130 chicks were hatched from non-sib matings of four males and nine females homozygous for ALV6. Eight males and 32 females will be selected for breeding to reestablish the 0.ALV6 homozygous line. Line 0.ALV6 chickens and embryos remain available to the public upon request. Key Words: Transgenic chicken, Avian leukosis virus, Genetic resource.