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Journal article

Aberrant low expression level of bovine beta-lactoglobulin is associated with a C to A transversion in the BLG promoter region.

  • Braunschweig MH Institute of Genetics, University of Berne, CH-3001 Berne, Switzerland. martin.braunschweig@itz.unibe.ch
  • Leeb T
  • 2006-10-13
Published in:
  • Journal of dairy science. - 2006
Alleles
Animals
Base Sequence
Cattle
Female
Gene Expression
Lactoglobulins
Male
Milk
Milk Proteins
Molecular Sequence Data
Polymerase Chain Reaction
Polymorphism, Single Nucleotide
Promoter Regions, Genetic
Sequence Alignment
English Beta-lactoglobulin (beta-LG) is the major whey protein in cow's milk. It is well established that the predominant 2 genetic variants, beta-LG A and B, are differentially expressed. Extensive investigation of the genetic variation in the promoter region of the BLG gene revealed the existence of specific haplotypes associated with the A and B variants, respectively. However, the genetic basis for the differential expression of BLG A and B alleles is still elusive. We have previously reported a quantitative beta-LG B variant, characterized by a very low beta-LG protein expression level. Here, we report that the corresponding BLG allele (BLG B*) shows a correspondingly low mRNA expression level. Comparative DNA sequencing of 7,670 bp of the BLG B* allele and the established BLG B allele revealed a unique difference of a C to A transversion at position 215 bp upstream of the translation initiation site (g.-215C>A). This mutation segregated perfectly with the differential phenotypic expression in a paternal half-sib family and could be confirmed in 2 independent cases. The sequence of the BLG B allele in the region of the mutation is highly conserved among 4 related ruminant species. The site of the mutation corresponds to a putative consensus-binding sequence for the transcription factors c-Rel and Elk-1 as predicted by searching the TRANSFAC database. The beta-LG B* site might be relevant in the natural production of milk of low beta-LG content.
Language
  • English
Open access status
bronze
Identifiers
Persistent URL
https://sonar.ch/global/documents/218701
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