Polymorphisms within the lactoferrin gene promoter in various cattle breeds.

Lactoferrin (Lf) is an iron-binding protein and belongs to the serum transferrin family. It has broad spectrum antimicrobial action, and it is found in exocrine secretions including milk. The sequence of the bovine lactoferrin gene promoter was analyzed in five different cattle breeds (Holstein Friesian, New Zealand Holstein, Montebéliard, Normande, and Norwegian Red) to determine the extent of polymorphic variation, which exists in this region both within and across cattle breeds. Fifteen different single nucleotide polymorphisms (SNPs) were identified throughout this region. Numerous polymorphisms were found throughout the Holstein Friesian, New Zealand Holstein, Montebéliard, and Normande populations. The most frequently encountered polymorphism found in all breeds was at position -28, which is immediately proximal to the TATA box of the promoter. The most variable base position was -131, which included three types of heterozygotes including a single base deletion in one allele, and three homozygote variants. This polymorphism occurs in a putative transcription factor binding site, for the nuclear factor of activated T cells (NF-ATc). A unique polymorphism was identified in one Normande animal, and three polymorphisms were found in one Montebéliard animal. In general, Norwegian Red cattle displayed fewer SNPs than other breeds. Most nucleotide changes in these animals were within the 190 base pairs of the transcription start point, with the exception of an insertion seen in three animals at position -478. In conclusion, SNPs were found in abundance throughout this regulatory region. Whether or not these polymorphisms have an effect on the regulation of the bovine lactoferrin gene is yet to be elucidated. However, the identification of lactoferrin promoter variants may serve as a marker for healthier animals, thereby accelerating the improvement of animals through breeding.