Promoter CpG methylation status affects ADRP gene expression level and intramuscular fat content in pigs

Abstract

Adipose differentiation-related protein (ADRP) is a lipid droplet-associated protein that is expressed early during adipose differentiation. However, the underlying mechanism is still unclear. In this study, the porcine ADRP (pADRP) gene regulatory mechanism and its relationship to intramuscular fat (IMF) content are analysed. We investigated the characteristics of the pADRP gene prompter as well as its transcription level, core promoter and epigenetic modification status using real-time PCR, Dual-luciferase reporter assays and bisulphite sequencing. The results showed that pADRP mRNA expression in Longissimus Dorsi (LD) muscle of the low IMF (LEAN) group was lower than that in the high IMF (FAT) group (p<.01). Maximum promoter activity was found in the −926 bp to −235 bp region. The methylation level of the pADRP of this region (mainly 7th, 10th, 12th CpG sites) in the low IMF group (86.67%) was significantly higher than that in the high IMF group (46.7%) (p<.01). Our result plays an important role in pADRP transcriptional regulation and provides a good prospect for the marbling traits improvement. Highlights pADRP expression differs in divergent IMF content pigs. Promoter region located −929 to −235 bp, and its methylation contributes to gene expression.