Patent ID: 8030538

Claim:
A bovine beta-casein gene targeting vector comprising, in operable association, (1) a first nucleic acid region having a length of about 6 kb which comprises the promoter and its flanking nucleic acid sequences of a bovine beta-casein gene, and further comprises exon 1, intron 1, and exon 2 of a bovine beta-casein gene; (2) a region for cloning a nucleic acid coding for desired proteins; (3) a region for coding a positive selection marker; (4) a second nucleic acid region having a length of 2.8 to 3.5 kb which comprises exon 5, 6, 7 and 8, and intron 5, 6 and 7 of bovine beta-casein gene; wherein the nucleic acid segment corresponding to the first region is located upstream to the nucleic acid segment corresponding to the second region in the 5′ -3′ arrangement of beta-casein gene.