Cloning, Sequence Characterization of Binglangjiang Buffalo Gene LALBA

Purpose α-lactlbumin which is encoded by LALBA gene plays an important role in biosynthesis of lactose. In recent years, LALBA is found to have close relationship with milk production traits of Holsteins cows, but few studies are reported in buffalo. To elucidate the sequence characteristics of buffalo LALBA gene.Method the complete coding sequence of the Binglangjiang buffalo LALBA gene was cloned using RT-PCR sequencing and the data obtained were analyzed by functional bioinformatics method in this study.Results Whole coding region of the buffalo LALBA gene in length is 429 bp which encodes a polypeptide composed of 142 amino acids. Buffalo LALBA contains a C-type lysozyme/alpha-lactalbumin family domain (AA20-138) and a signal peptide sequence (AA19-20), without transmembrane domains. This protein has 4 kinds of functional active site. It is an extracellular secreted and hydrophilic protein with a hydrophobic N-terminal and a hydrophilic C-terminal. Phylogenesis analysis based on the sequences of LALBA coding region shows that Binglangjiang buffalo clustered with other bovine species, which indicated that the functional similarity of LALBA gene in the family of Bovidae. Five SNPs were identified in Binglangjiang buffalo LALBA gene, viz. c.63A>G, c.107A>G, c.147A>G, c.249C>T and c.291T>C. All these variants were in Hardy-Weinberg disequilibrium and only the SNP107 was a nonsynonymous substitution leading to corresponding coded amino acid change from aspartic acid to glycine, but this change has no effect on the function of buffalo LALBA protein by functional analysis.Conclusion The results revealed that the buffalo LALBA gene is the same in length with other bovine and its coding. Polypeptide has similar structure and function with other bovine species. This study will lay a foundation for further study on the functional mechanism of buffalo LALBA in the process of lactation.