Epigenetic Regulation of the GnRH and Kiss1 Genes: Developmental Perspectives

Gonadotropin-releasing hormone (GnRH) and kisspeptin neurons are indispensable for reproductive function. This chapter focuses on the epigenetic regulation of the GnRH and kisspeptin (Kiss1) genes in the context of neuronal development, puberty onset, and maintenance of adult reproductive function. Proper function of GnRH and kisspeptin neurons in the hypothalamus requires coordinated embryonic and postnatal maturation. Recent studies indicate that diverse epigenetic phenomena including the formation of chromatin loops, activation of bivalent domains, maintenance of “stable” histone modifications, and DNA methylation, active demethylation, and hydroxymethylation are all involved in epigenetic regulation of these neurons. This chapter focuses on how these epigenetic regulation components interact with each other and which enzymes or binding factors are involved in specific stages of neuronal development or aging. By emphasizing similar epigenetic mechanisms operating within these two peptidergic neuronal populations, we highlight likely targets for future investigations of environmental influences over puberty timing and progression.