Development of transgenic chickens expressing bacterial β‐galactosidase

Abstract
Replication-defective retroviral vectors are efficient vehicles for the delivery of exogenous genes, and they may be used in the generation of transgenic animals. The replication-defective retroviral SNTZ vector carrying the lacZ gene with a nuclear localized signal was injected into the subgerminal cavity of freshly laid eggs. Subsequently, the eggs were allowed to hatch, and the chickens were screened for the lacZ gene by using the polymerase chain reaction. Eight of 15 male chickens that survived to sexual maturity contained the lacZ gene in their semen. Subsequently, these males were mated with wild-type female chickens. From one of the eight lacZ-positive G0 males, two lacZ-positive male chickens were produced from a total of 224 G1 progeny for a germline transmission rate of 0.89%. Both G1 male chickens carrying the lacZ gene were mated with wild-type female chickens and 46.5% of the G2 progeny contained the lacZ gene, which is consistent with the expected Mendelian 50% ratio for a heterozygous dominant allele. The product of the lacZ gene, nuclear localized β-galactosidase, was expressed in primary myoblast cultures derived from G2 chickens, and it was also expressed in whole G2 chicken embryos. Developmental Dynamics, 2003.