DNA methylation of CpG sites in the chickenKLF7promoter and Exon 2 in association with mRNA expression in abdominal adipose tissue and blood metabolic indicators

Background Our previous study found that chicken KLF7 was an important regulator in formation of adipose tissue. In the present study, we analyzed the association for DNA methylation in chickenKLF7with its transcripts of abdominal adipose tissue and blood metabolic indicators. Results TheKLF7transcripts of the adipose tissue of Chinese yellow broilers were associated with age (F = 6.67,P = 0.0035). In addition, theKLF7transcripts were negatively correlated with blood glucose levels (r = - 0.61841,P = 0.0140). The DNA methylation levels of 26 CpG loci in the chickenKLF7promoter and Exon 2 were studied by Sequenom MassArray. A total of 22 valid datasets were obtained. None of them was significantly different in relation to age (P > 0.05). However, the DNA methylation levels in the promoter were lower than those in Exon 2 (T = 40.74,P < 0.01). Correlation analysis showed that the DNA methylation levels of PCpG6 and E2CpG9 were significantly correlated withKLF7transcripts and blood high-density lipoprotein levels, respectively, and many CpG loci were correlated with each other (P < 0.05). The methylation data were subjected to principal component analysis and factor analysis. The six principal components (z1-z6) were extracted and named Factors 1-6, respectively. Factor analysis showed that Factor 1 had a higher load on the loci in the promoter, and Factors 2-6 loaded highly on quite different loci in Exon 2. Correlation analysis showed that only z1 was significantly correlated toKLF7transcripts (P < 0.05). In addition, an established regression equation between z1 andKLF7transcripts was built, and the contribution of z1 to the variation onKLF7transcripts was 34.29%. Conclusions In conclusion, theKLF7transcripts of chicken abdominal adipose tissue might be inhibited by DNA methylation in the promoter, and it might be related to the DNA methylation level of PCpG6.