Differential allelic expression of lactoproteins: a model to study transcriptional regulation

The importance of transcriptional control of gene expression has been documented in relation to several genetic defects in man. Mutations in the promoter region of genes have been shown to be responsible for defects which are characterized by over or under expression of genes. Genetic polymorphisms of the milk protein genes, and their high level of tissue specific expression during lactation, represent a suitable system for studying regulation of gene expression. Quantification of the allele specific protein products has demonstrated unequal allelic contribution in the expression of the beta lactoglobulin (beta-LG) alleles A and B. The DNA sequence analysis of the beta-LG promoter revealed allele specific polymorphisms related to the coding region genotypes.