DNA variants within the 5′-flanking region of milk-protein-encoding genes II. The β-lactoglobulin-encoding gene

✍ Scribed by V. A. Wagner; T. A. Schild; H. Geldermann

• Publisher: Springer
• Year: 1994
• Tongue: English
• Weight: 835 KB
• Volume: 89
• Category: Article
• ISSN: 0040-5752
• DOI: 10.1007/bf00226993

✦ Synopsis

For the detection of polymorphisms within the 5'-flanking region of the β-lactoglobulin (-LG) -encoding gene a nucleotide sequence containing 795 bp of the promoter and 59 bp of exon I was cloned and sequenced. After comparing the sequence from the DNA of 11 diverse cows (different breeds and milk-protein yields), 14 singlebp substitutions were identified within the 5'-flanking region and two in the 5'-untranslated region (5'-UTR) of exon I. Some of the variants are located in potential binding sites for trans-acting factors or in the 5'-UTR. A PCR-based RFLP analysis was performed, and the genotypes of an additional 60 cows were identified at five variable 5'-flanking sites. The results reveal three frequent combinations between the A and B alleles of the protein-coding region and the novel 5'-flanking DNA variants. This finding may explain the differences of the protein-variant-dependent β-LG synthesis (A>B) observed in vivo. A sequence comparison of the bovine and ovine promoters reveals an homology of 92.8% and shows a higher degree of conservation between positions -600 and -300.