LXRα gene expression, genetic variation and association analysis between novel SNPs and growth traits in Chinese native cattle.

Liver X receptor α (LXRα) has emerged as an important regulator of lipid and energy metabolism. In this study, to better understand the effects of LXRα gene on growth traits in cattle, the mRNA tissue expression patterns and the polymorphisms of some exons of LXRα were revealed. The expression profile of the bovine LXRα gene was detected by quantitative real-time polymerase chain reaction (qRT-PCR) in 11 different Jiaxian cattle tissues and was found mainly expressed in spleen, liver, fat tissue, kidney, muscle, and lung. Meanwhile, it showed that four single nucleotide polymorphisms (SNPs), named g.1028 T>C, g.1514 T>C, g.2929G>A, and g.3493 T>C, were detected and 12 different haplotypes were constructed. Haplotype with CCGT was dominant with frequency of 40.8 %. There was a strong link between g.1028 T>C and g.1514 T>C (r (2) = 0.374). Association analysis of SNPs with growth- and body-related traits was carried out in 445 Chinese native cattle. The results displayed that the heterozygous genotypes of g.1028 T>C and g.1514 T>C showed a molecular heterosis on four performance traits related to body size: height at withers, body length, hipbone width, and hip width (P < 0.05). The multiple effects of four sites showed that the height at withers, body length, hipbone width, and hip width of individuals of TC-TC-GG-TT combined genotypes were significantly higher than other genotypes (P < 0.05). The effects of the four loci genotype combination on conformation traits were consistent with the effects of g.1028 T>C and g.1514 T>C loci. The SNPs of g.1028 T>C and g.1514 T>C of the bovine LXRα gene could be potential genetic markers for growth traits in cattle. These results suggest that LXRα gene is expressed in many tissues and may provide primary molecular information for further studies on body size traits in Chinese indigenous cattle.