A novel SNP of the ATP1A1 gene is associated with heat tolerance traits in dairy cows.

PCR low ionic strength single-strand conformation polymorphism (PCR-LIS-SSCP) and DNA sequencing methods were used to analyze the polymorphisms within the coding region of bovine ATP1A1 gene. A novel C/A mutation was identified at the nucleotide position 2789 of the ATP1A1 mRNA, but it was silent with respect to the amino acid sequence of the protein. The LIS-SSCP banding pattern could be divided into three kinds of genotypes, named CC, CA, and AA. Also, the association of the novel SNP of ATP1A1 gene with heat tolerance traits was studied, we found that the individuals with genotype CC showed significantly higher heat resistance than those of genotype CA (P<0.05). Further, the mRNA levels of ATP1A1 gene in lymphocytes of peripheral blood in dairy cows among various temperature groups and genotypes were analyzed by using real-time RT-PCR. Results showed that the expression of ATP1A1 mRNA was highest in heat-stressed cows with CC genotype among the three genotypes (P<0.01), and the ATP1A1 mRNA level at temperature 32.5°C was higher than that at optimal temperature 12.5°C in dairy cows (P<0.01). Simultaneity, the plasma potassium (K+, mmol/l) and sodium (Na+, mmol/l) declined when the temperature dropped (P<0.05). Our findings implied that the novel SNP here could be a potential genetic marker for anti-heat stress trait in dairy cow breeding.