Promoter and first exon methylation regulate porcine FASN gene expression

DNA methylation is a stable epigenetic mark mediating gene expression. Methylation is crucial for diverse biological processes, including aging and embryo development. FASN (fatty acid synthase) plays an important role in de novo lipogenesis, through catalyzing the reductive synthesis of long-chain fatty acids. In this study, we investigated the FASN gene expression pattern and corresponding DNA methylation status in the inner layer of backfat from Jinhua pigs at different developmental stages. Our results showed that FASN gene expression increases with age and is positively associated with adipocyte volume (r = 0.98, P < 0.01). In addition, the DNA methylation level for the first exon (0.11, CGI 3) of the FASN gene is approximately 8-fold lower than levels for its promoter (0.94, CGI 1&2) (two-way ANOVA, PCGI < 0.01). The association analysis revealed that both promoter (r = -0.944, P < 0.01) and first exon methylation (r = -0.774, P < 0.01) are significantly and negatively correlated with FASN gene expression. Our results will benefit future investigations of the epigenetic mechanism underlying FASN gene expression.