Expression of HBsAg gene in transgenic goats under direction of bovine alpha-S1 casein control sequence

An expressive construct combining hepatitis B surface antigen gene and bovine alpha-S1 casein control sequence (a 16-kb fragment), lambda 106, was made successfully using DNA recombination technology. The construct was then introduced into fertilized goat eggs with a transgenic technique. As the eggs developed into adults which, in turn, began to secrete milk after parturition, ELISA assay demonstrated HBsAg in the milk, thus showing successful expression of the construct in the mammary gland of the G0 transgenic goats and the secretion of the expression product into the milk.