ISOLATION, BIOINFORMATIC AND TISSUE EXPRESSION ANALYSIS OF A NOVEL WATER BUFFALO GENE-BTN1A1

Butyrophilin 1a1 (BTN1A1) is a milk fat globule membrane protein and plays a crucial role in the secretion of milk lipid and milk lactation. In the present study, water buffalo BTN1A1 cDNA was isolated and characterized. The full-length CDS of BTN1A1 from the water buffalo mammary gland consists of 1581 nucleotides, which encodes 526 amino acids with a molecular weight of 49.26 kDa and a pI of 5.05. Bioinformatic prediction indicates that the protein contains one signal peptide in its N-terminal side, and belongs to a hydrophilic single-pass transmembrane protein located in the cytoplasm. The CDS sequence of BTN1A1 in water buffalo had 100%, 99%, 97% and 97% identity with that of cattle, yak, goat and sheep, respectively. There was no polymorphism found in water buffalo BTN1A1. The phylogenetic tree constructed based on the amino acid sequences of BTN1A1 from all sixteen species revealed that the water buffalo has closer genetic relationship with the species of bovidae family, which suggested that the function of water buffalo BTN1A1 is similar to that of other bovine species. Quantitative PCR (qPCR) analysis shows that the water buffalo BTN1A1 gene is mainly expressed in mammary gland, with little or no expression in other tissues, which indicates BTN1A1 plays a crucial role in the secretion of milk lipid and milk lactation.