Polymorphisms of beta-lactoglobulin promoter region in three Sicilian goat breeds

Several beta-lactoglobulin (BLG) polymorphismshave been described within the proximal promoterregion and coding region of the caprine gene, although nogenetic variants affecting the protein amino acid compositionand/or expression level have been characterized sofar. Binding sites for several transcription factors (TFs) arepresent in the BLG promoter region. The aims of this workwere to sequence the full-length promoter region of threeSicilian goat breeds in order to identify polymorphisms,analyze the identified haplotypes, search for differencesbetween breeds for the presence of polymorphisms in thisgene region, search for putative TFs binding sites, andcheck if polymorphisms lay within the identified TFsbinding sites. The promoter region of BLG gene in Siciliangoat breeds showed high level of polymorphism due to thepresence of 36 single nucleotide polymorphisms (SNPs).Association between polymorphic sites was computedwithin the whole sample analyzed and 18 haplotypes wereinferred. Binding sites for three milk protein binding factors (MPBFs) and four nuclear factor-I (NF-I) werefound within BLG promoter region based on the ovinesequence. The identification of some SNPs within TFsbinding sites allowed hypothesizing the loss of TFs. Furtherstudies are in progress to evaluate the effect of thesemutations on binding affinity of TFs, the functional interactionof the TFs with the goat BLG promoter, and therelationship of the polymorphisms with BLG geneexpression and milk production and composition.