Gene transfer in swine embryos by injection of cells infected with retrovirus vectors

Abstract
Key components for gene transfer to swine embryos using an avian retrovirus are described. A replication-defective reticuloendotheliosis (REV) viral vector can infect and be expressed in pig embryo fibroblasts (PEF). Infection with a replication-competent vector (REV-A) indicates a presumptive block to viral replication in PEF. Swine embryos obtained at the morula stage can be cultured in vitro to the blastocyst stage, injected with retrovirus helper cells or quail embryo fibroblasts producing REV, and transferred to recipient swine with survival to at least 6 wk of gestation.