Detection of polymorphisms in the promoter of bovine SIRT1 gene and their effects on intramuscular fat content in Chinese indigenous cattle.

Intramuscular fat content (IMF) is one of the most significant factors for meat quality affecting tenderness, flavor, and juiciness of meat. For this reason, we aimed to investigate the association of SIRT1 gene polymorphisms with intramuscular fat content in Chinese Qinchuan cattle (Bos taurus). Using DNA sequencing, three single nucleotide polymorphisms (SNPs) within the promoter regions of SIRT1 gene were identified in 535 Qinchuan cattle, and the five haplotypes representing five potential different compositions of polymorphic potential cis-acting elements. Results indicated that both c.-107 G>A and c.-274 A>G were significantly associated with intramuscular fat content in Qinchuan cattle, and Hap5/5 diplotype showed higher (P < 0.05) intramuscular fat content than other combinations (P < 0.05 or P < 0.01). In addition, the Hap5 haplotype had much lower (P < 0.05) transcriptional activity, consistent with the association analysis. Based on our results, the polymorphisms in transcription factor binding sites of SIRT1 gene promoter may affect the transcriptional activity of SIRT1 gene, and thus alter intramuscular fat content in beef cattle.