Cloned kids derived from caprine mammary gland epithelial cells

The use of nucleus transfer techniques to generate transgenic dairy goats capable of producing recombinant therapeutic proteins in milk could have a major impact on the pharmaceutical industry. However, transfection or gene targeting of nucleus transfer donor cells requires a long in vitro culture period and the selection of marker genes. In the current study, we evaluated the potential for using caprine mammary gland epithelial cells (CMGECs), isolated from udders of lactating F1 hybrid goats (Capra hircus) and cryopreserved at Passages 24 to 26, for nucleus transfer into enucleated in vivo-matured oocytes. Pronuclear-stage reconstructed embryos were transferred into the oviducts of 31 recipient goats. Twenty-three (74%), 21 (72%), and 14 (48%) recipients were confirmed pregnant by ultrasonography on Days 30, 60, and 90, respectively. Four recipients aborted between 35 and 137 d of gestation. Five recipients carried the pregnancies to term and delivered one goat kid each, one of which subsequently died due to respiratory difficulties. The remaining four goat kids were healthy and well. Single-strand conformation polymorphism analysis confirmed that all kids were clones of the donor cells. In conclusion, the CMGECs remained totipotent for nucleus transfer.