Two completely linked polymorphisms in thePPARGtranscriptional regulatory region significantly affect gene expression and intramuscular fat deposition in the longissimus dorsi muscle of Erhualian pigs

Abstract

This article is the first to report the significant effect of PPARG promoter polymorphisms on the expression and intramuscular fat (IMF) content in the longissimus dorsi (LD) muscle of Erhualian pigs. Polymorphic sites for the PPARG upstream transcriptional regulatory region were scanned by direct sequencing of two DNA pools consisting of individuals with significantly different IMF content (P < 0.05). Two SNPs (c.-1633C>T and c.-1572G>A) were identified, with different allele distribution between these two groups. A total of 66 Erhualian pigs and 24 Yorkshire × Large White (Y × L) pigs were genotyped for these two SNPs using PCR-SSCP (single-strand conformation polymorphism), which exhibited that only the T-A and C-G haplotypes existed. The T-A type promoter was found to have higher activity than G-C type promoter for PPARG gene transcription in the induced preadipocytes using luciferase assay. In addition, the frequency of the T-A type in Erhualian pigs was much higher than that in the Y × L pigs (35.6% vs. 8.3%), and in fact, no T-A/T-A samples were found in Y × L pigs. Therefore, we conclude that the T-A haplotype of PPARG is a desirable form that might contribute to the relatively higher IMF content in Erhualian pigs.

The Differential Expressions of PPARγ and CAST mRNA in Muscle Tissues of Jinhua and Landrace Pigs

“…PPARγ is involved in the adipocyte differentiation and improved IMF deposition and adipogenesis in muscle fibers which determines IMF content (Wang et al, 2013). In the present experiment, the PPARγ expression in muscle tissues of Jinhua and Landrace pigs was significantly and positively correlated with IMF content.…”

Muscle Transcriptome Analysis Reveals Potential Candidate Genes and Pathways Affecting Intramuscular Fat Content in Pigs

“…PPARG regulates lipid metabolism and glucose homeostasis and promotes adipocyte differentiation and fat deposition (Vanden Heuvel and Peters, 2010). Previous studies have found that the polymorphisms of PPARG could significantly affect gene expression and intramuscular fat deposition in pigs (Wang et al, 2013). In addition, PPARG could enhance PLIN1 expression by DNA demethylation on PPAR-response elements of PLIN1 gene promoter upon differentiation (Fujiki et al, 2013).…”

Intermuscular and intramuscular adipose tissues: Bad vs. good adipose tissues

“…141 Furthermore, the polymorphism in the PPARg (TA haplotype favorable over CG haplotype) upstream transcriptional regulatory region has been associated with higher IM. 174 On the contrary, a few other GWA have had limited success in the identification of the genetic drivers of IM percentage which could be due to variations including treatments, genetics etc., resulting in the similar phenotype. 175,176 High throughput genomic technologies using powerful SNP panels will have to be combined with phenomics approach to further understand the complexities of IM.…”