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.

Genetic variants in the SIRT6 transcriptional regulatory region affect gene activity and carcass quality traits in indigenous Chinese beef cattle (Bos taurus).

BACKGROUND: The aim of this study was to analyze potential influences of polymorphisms within the regulatory region of the bovine SIRT6 gene on carcass quality traits. Expression analyses suggested that SIRT6 gene is predominately expressed in kidney, compared with other tissues. In 535 indigenous Chinese beef cattle, two novel single nucleotide polymorphisms (SNPs) were identified within the promoter region of the SIRT6 gene. RESULTS: Association analysis indicated that G allele of the c.-1100 A > G had a positive effect on fat deposition, and the Hap4/4 diplotype had more favourable results than other dipoltypes with respect to the evaluation of carcass quality traits. Furthermore, promoter activity associated with the Hap3 haplotype was measured at higher levels than the Hap1 haplotype, which would be in agreement with the previously described association analysis. CONCLUSION: The SIRT6 promoter variants significantly affect transcriptional levels and subsequently significantly influence bovine intramscular fat content.