Production of transgenic miniature pigs by pronuclear microinjection

Miniature pig is an attractive animal for a wide range of research fields, such as medicine and pharmacology, because of its small size, the possibili ty of breeding it under minimum environmental controls and the physiology t hat is potentially similar to that of human. Although transgenic technology is useful for the analysis of gene function and for the development of mod el animals for various diseases, there have not yet been any reports on pro ducing transgenic miniature pig. This study is the first successful report concerning the production of transgenic miniature pig by pronuclear microin jection. The huntingtin gene cloned from miniature pig, which is a homologu e of candidate gene for Huntington's disease, connected with rat neuron-spe cific enolase promoter region, was injected into a pronucleus of fertilized eggs with micromanipulator. The eggs were transferred into the oviduct of recipient miniature pigs, whose estrus cycles were previously synchronized with a progesterone analogue. A total of 402 injected eggs from 171 donors were transferred to 23 synchronized recipients. Sixteen of them maintained pregnancy and delivered 65 young, and one resulted in abortion. Five of the 68 offspring (three of which were aborted) were determined to have transge ne by PCR and Southern analysis. The overall rate of transgenic production was 1.24% (transgenic/injected eggs). This study provides the first success and useful information regarding production of transgenic miniature pig fo r biomedical research.