Epigenetic regulation of a mouse PPARγ splicing variant, Pparγ1sv, during adipogenesis in 3T3-L1 cells

We have previously reported the abundant and ubiquitous expression of a newly identified splicing variant of mouse peroxisome proliferator-activated receptor-{gamma} (Ppar{gamma}), namely Ppar{gamma}1sv that encodes PPAR{gamma}1 protein, and plays an important role in adipogenesis. Ppar{gamma}1sv has a unique 5UTR sequence, compared to those of mouse Ppar{gamma}1 and Ppar{gamma}2 mRNAs. This implies the presence of a novel transcriptional initiation site and promoter for Ppar{gamma}1sv. We found that DNA methylation of 42 CpG sites in the proximal promoter region (-733 to -76) of Ppar{gamma}1sv was largely unchanged five days after adipocyte differentiation, whereas chromatin immunoprecipitation-quantitative PCR (ChIP-qPCR) using antibodies against H3K4me3 and H3K27ac revealed that these modifications significantly elevated at the transcription start sites of Ppar{gamma}1sv and Ppar{gamma}2 after differentiation.