Casein Kappa (CSN3)

KCA gene extends over 8,821 nucleotides and consists of 5 exons ranging from 33 to 496 nucleotides separated by introns ranging from 1,146 to 2,942 nucleotides. The human and bovine KCA genes are very similar, with a conserved gene organization and observed identities of 81% and 87% for exons 1 and 2, respectively.

The human alpha-S1-casein, beta-casein, and kappa-casein genes are closely linked and arranged in that order. The distance between the alpha-S1 and beta and between alpha-S1 and kappa is approximately 10 and 300 kb, respectively. The beta-casein gene is oriented in the opposite direction to the alpha-S1 and kappa genes. By fluorescence in situ hybridization, the casein gene family was localized to 4q21.1.