Methylation pattern variation between goats and rats during the onset of puberty

Abstract

Puberty is initiated by increased pulsatile gonadotropin-releasing hormone (GnRH) release from the hypothalamus. Epigenetic repression is thought to play a crucial role in the initiation of puberty, although the existence of analogous changes in methylation patterns across species is unclear. We analysed mRNA expression of DNA methyltransferases (DNMTs) and methyl-binding proteins (MBPs) in goats and rats by quantitative real-time PCR (qRT-PCR). DNA methylation profiles of hypothalamic were determined at the pre-pubertal and pubertal stages by bisulphite sequencing. In this study, expression of DNMTs and MBPs mRNA showed different patterns in goats and rats. Global methylation variation was low in goats and rats, and the profile remained stable during puberty. Gene ontology (GO) and Kyoto Encyclopedia of Gene and Genomes (KEGG) pathway analysis revealed the involvement of 62 pathways in puberty in goats and rats including reproduction, type I diabetes mellitus and GnRH signalling pathways and found that Edn3, PTPRN2 and GRID1 showed different methylation patterns during puberty in goats and rats and similar variation patterns for Edn3 and PTPRN2 were showed. These indicated that Edn3 and PTPRN2 would play a role in the timing of puberty. This study provides evidence of the epigenetic control of puberty.