Bovine κ-Casein Gene Promoter Haplotypes with Potential Implications for Milk Protein Expression

Promoter haplotypes of κ-CN in relation to potential transcription factor binding sites. A. Haplotypes (A and B) in the bovine κ-CN promoter sequence are aligned across the 3 linked polymorphic sites (single nucleotide polymorphisms highlighted with white text in gray box). Transcription factor binding sites potentially affected by the polymorphism are given below the sequence, and the nucleotide position is indicated above the sequence. The BclI site used for the RFLP screen (see C) is marked. B. Alignment across the 3 linked polymorphic sites of κ-CN promoter sequences from other species (for accession numbers, see the materials and methods section). The neighboring MGF binding site is also marked in bold.

κ-Casein promoter activity in MCF7 cells. Plasmids AK1 (505-bp promoter), AK2 (752-bp promoter), and AK3 (1.3-kb promoter) of both haplotypes (A and B) carrying the firefly luciferase reporter under the control of the various κ-CN promoter fragments were transfected into MCF7 cells together with a Renilla luciferase control vector. Luciferase values were expressed as a ratio of firefly to Renilla and corrected to the AK1-A value (100%). Results are from 4 independent experiments. Error bars show standard deviations for triplicates assayed in each experiment.