Production of Human TPA Transgenic Pigs by Somatic Cell Nuclear Transfer

Tissue-type plasminogen activator, a protein used to treat heart attacks, converts plasminogen into plasmine, which digests fibrin and induces the dissolution of fibrin clots. The purpose of this study was to produce a tPA transgenic pig by somatic cell nuclear transfer. The human tPA (htPA) genes were transfected into porcine ear fibroblast cells derived from a female piglet and established two transgenic cell lines (Tg) with normal karyotypes. Tg line #3 and #4, which expressed high levels of the transgenes. Blastocyst rates of SCNT embryos derived from Tg lines were significantly lower than those of Non-Tg. A total of 2799 SCNT embryos were transferred to 9 surrogates. Seven offspring were delivered, and the production efficiency was 1.0~1.3% (3/324 and 4/304). All offspring exhibited htPA genes. These piglets revealed by microsatellite testing to be genetically identical to Tg cell lines, but not to the surrogate. Our goal is to establish a htPA transgenic pig for studying biopharmaceutical production.