High expression of human serum albumin in milk of transgenic mice directedby the goat beta-casein gene promoter region

We have constructed a mammary gland expression vector that contained the go at beta casein gene promoter, 5 ' upstream regulatory region, exons 1, 2, i ntron 1 as well as the human serum albumin (hALB) mini-gene (including the full-long sequences of hALB cDNA and its intron 1), Injection of the vector into mouse tail veins showed that the recombinant construct was expressed only in mammary glands, The vector was microinjected into the mouse fertili zed eggs, followed by transferring the eggs into the foster mice. 33 F-0 mi ce were obtained. Of the 33, 8 mice (5 female, 3 male) were transgenic with hALB gene integration identified by PCR as well as Southern blot hybridiza tion, The integration rate was 24.2% (8/33), Western blot analysis showed t hat 3 female transgenic mice had hALB expression in their milk. The hALB co ntents in milk reached 3.54, 0.21 and 3.03 g/L, respectively.