Allelic differences in bovine kappa - CN gene which may regulate gene expression.
The most common kappa casein (κ-CN) variants, κ-CN A and κ-CN B, are synthesised differentially in the lactating mammary gland of heterozygous animals (κ-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 (κ-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 κ-CN proximal promoter region. Sequence analysis of the 3'-UTR of the κ-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 κ-CN in milk.
Genetic Laboratory, Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Groblje 3, 1230 Domžale, Slovenia, , , , , , SI.
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M
Debeljak
Genetic Laboratory, Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Groblje 3, 1230 Domžale, Slovenia, , , , , , SI.
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Sušnik
Laboratory of Microbiology, Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Groblje 3, 1230 Domžale, Slovenia, , , , , , SI.
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Marinšek-Logar
Department of Animal Science, University of California, One Shields Ave. Davis, CA 95616, USA, , , , , , US.
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Medrano
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Dovč
3’-UTR; Key words differential allelic expression; bovine κ-CN