Epigenetic regulation of Pax3 and Pax7 in an age-dependent manner in mouse skeletal muscle

Abstract

Pax3 and Pax7, members of the Pax gene family, are involved in organogenesis and tissue specification during embryogenesis. For better understanding of Pax3 and Pax7 transcriptional regulation during aging, I determined the mRNA levels of Pax3 and Pax7 using mouse skeletal muscle tissues of various ages by semi-quantitative RT-PCR. The mRNA levels of Pax3 and Pax7 decreased during aging. To investigate the epigenetic mechanism of transcriptional regulation, bisulfite sequencing analysis and chromatin immunoprecipitation (ChIP) assay were performed. DNA methylation changes of CpG island at the Pax3 and Pax7 promoter were examined using young and old mice. DNA methylation status of Pax3 and Pax7 was not significantly changed. ChIP assay was performed to investigate the correlation of the histone H3 lysine 9 (H3-K9) modifications with the decreased mRNA levels during aging. Histone H3-K9-trimethylation levels increased, however, histone H3-K9-acetylation levels decreased during aging. Bisulfite sequencing and ChIP assay reveals that Pax3 and Pax7 gene transcription is epigenetically regulated during aging by histone H3-K9-trimethylation, but not by DNA methylation.