Work

Photoperiodic responsiveness in the DNA methylation and gene expression in the hypothalamus of ovariectomized and estradiol-treated ewes

Year: 2025

Type: article

Abstract: BACKGROUND: ) Sunite ewes exposed to artificial short-day (SP) and long-day (LP) photoperiods. Integrated whole-genome DNA methylation and transcriptomic analyses were performed to elucidate the regulatory mechanisms underlying photoperiod-mediated seasonal reproduction. RESULTS: The DNA methylation profiles of the hypothalamus were examined, and whole-genome single-base resolution methylome maps of the sheep hypothalamus were generated across seven time points under various photoperiod treatments. The results revealed that photoperiod-induced changes in genome-wide DNA methylation constitute a dynamic and reversible regulatory process, with a potential transition point occurring approximately 15 days after the switch from SP to LP. Following integrated analysis of differentially methylated regions-related genes (DMRGs) and differentially expressed genes (DEGs), it showed that the DNA methylation levels before the transcription start site (TSS) of the overlapping gene were different, and a negative correlation between gene expression levels and mCG levels in gene promoters was found (P < 0.01). Functional analysis of the overlapping genes revealed that pathways involved in synapse development, thyroid hormone signaling, and circadian rhythm were regulated by photoperiod-induced DNA methylation, thereby influencing hypothalamic function in photoperiod-dependent seasonal reproduction. CONCLUSION: This study generated the whole-genome single-base resolution DNA methylome maps of sheep hypothalamus under different photoperiods, and elucidated the regulatory relationship between DNA methylation and photoperiod-dependent seasonal reproduction in sheep hypothalamus tissues. Our findings provided a valuable resource for further research on the underlying mechanisms of the hypothalamic-regulated reproductive seasonality in sheep.

Source: BMC Genomics

DOI: 10.1186/s12864-025-12066-y