Allelic differences in bovine kappa -- CN gene which may regulate gene expression

• Published in: Pflügers Archiv 2000-07, Vol.439 (7), p.R4
• Main Authors: Debeljak, M, Susnik, S, Marinsek-logar, R, Medrano, J F, Dovc, P
• Format: Article
• Language: English
• ISSN: 0031-6768; 1432-2013
• DOI: 10.1007/BF03376502

The most common kappa casein ([kappa]-CN) variants, [kappa]-CN A and [kappa]-CN B, are synthesised differentially in the lactating mammary gland of heterozygous animals ([kappa]-CN AB). In this study we evaluated several approaches for quantification of allele specific mRNA transcripts. The most consistent results were obtained using allele specific RT-PCR and capillary electrophoresis. On average, 13.4% more allele B specific than A specific transcripts were found. DNA sequencing of the proximal promoter region in several homozygous animals ([kappa]-CN AA, BB, EE) did not reveal any allele specific polymorphisms. Using the EMSA and DNase I footprinting we confirmed functional binding sites for three transcription factors (AP-2, NF1 and MGF) within the [kappa]-CN proximal promoter region. Sequence analysis of the 3'-UTR of the [kappa]-CN gene revealed seven allele specific sites. Two of these allelic differences were close to previously identified 3'-end regulatory sequences. In addition, allele specific differences in length between mRNAs of both variants were found. The two later findings suggest a possible post translational control determining content differences of [kappa]-CN in milk.