Polymorphisms of the kappa casein (<i>CSN</i>3) gene and inference of its variants in water buffalo (<i>Bubalus bubalis</i>)

Abstract

Kappa casein plays a crucial role in the formation of stable casein micelles and has a key influence on milk-clotting properties. However, current understanding of buffalo CSN3 gene polymorphisms is not sufficient. In this study, the polymorphisms in the complete coding sequence (CDS) of the buffalo CSN3 were detected using PCR product direct sequencing. The CDS of CSN3 for river and swamp buffalo was the same in length, which contained an open reading frame of 573 nucleotides encoding a peptide containing 190 amino acid residues. A total of eight single nucleotide polymorphisms (SNPs) was identified in two types of buffalo. Among them, c.86C>T, c.252G>C, c.445G>A, c.467C>T and c.516A>C were non-synonymous, which leads to p.Pro8Leu, p.Lys63Asn, p.Val128Ile, p.Thr135Ile and p.Glu151Asp substitutions in buffalo kappa casein (italicκ-CN), respectively. The substitution of p.Thr135Ile may exert a vital effect on the function of buffalo italicκ-CN. Eleven haplotypes were defined based on the SNPs found in buffalo, and accordingly, seven protein variants and four synonymous variants of buffalo italicκ-CN were inferred, called variants A, B, B1, C, C1, C2, D, E, F, F1 and G. The variants observed in water buffalo did not exist in the Bos genus. In addition, 14 amino acid differential sites of italicκ-CN between buffalo and the Bos genus were identified, of which 3 were located at glycosylation sites (80S, 96T, 141S) and 4 at phosphorylation sites (19S, 80S, 96T, 141S). It is speculated that they may lead to differences in the physicochemical properties of italicκ-CN between buffalo and the Bos genus. This study will lay a foundation for exploring the association between the variation in the CSN3 gene and the lactation traits of buffalo.

Polymorphism and molecular characteristics of the <i>CSN1S2</i> gene in river and swamp buffalo

“…It can provide the suckling infant with amino acids, calcium and phosphate and is related to lactation traits of dairy animals and milk processing characteristics (Boettcher et al, 2004;Wedholm et al, 2006;Nilsen et al, 2009). The CSN1S2 gene encodes α S2 -CN, which accounts for 10 % of the total CN in the milk of dairy cows (Farrell et al, 2004). The α S2 -CN, together with α s1 -CN and β-CN, is called a calcium-sensitive protein which can form stable micelles with calcium and phosphorus to support bone growth in the young (Lefèvre et al, 2009;Corral et al, 2013).…”

“…The cattle CSN1S2 gene has been mapped in chromosome 6 and contains 18 exons, of which exon 1 is located in the 5 untranslated region (UTR), exon 2 encodes the signal pep-tide from the 13th nucleotide, exons 3-16 are located in the coding sequence (CDS) region and encode a mature peptide, and exons 17-18 are in the 3 UTR. The CDS length is 669 bp and encodes a protein consisting of 222 amino acids (AAs), of which the first 15 AAs form an N-terminal signal peptide (Farrell et al, 2004). The α S2 -CN variants in the Bos genus have been widely studied for many years.…”

Validation of Bos taurus SNPs for Milk Productivity of Sahiwal Breed (Bos indicus), Pakistan

“…The association of this SNP with milk yield and milk protein content is biologically plausible, as κ-casein is a major component of milk proteins and plays a significant role in casein micelle structure, stability, and milk coagulation [41].…”

Molecular Characteristics and Polymorphisms of Buffalo (Bubalus bubalis) ABCG2 Gene and Its Role in Milk Fat Synthesis

“…Domestic buffaloes are classified into two categories: river and swamp buffaloes. The former are primarily utilized for milk production, with each lactating buffalo producing more than 2000 kg of milk per year, while the latter are predominantly employed for draught purposes, with each lactating buffalo producing 500-600 kg of milk per year [14]. Although buffaloes are critical for agricultural development, compared with other domestic animals, genomic evaluation studies in buffaloes are still in the developing stage [15].…”