Fig. 1

Schematic experimental design of an artificial photoperiod program performed to induce the activation of the HPG axis in male quails. The mediobasal hypothalamic tissues of male Japanese quail were collected under SD28, LD3, LD7, and LD28 conditions, and accessible chromatin was detected by high throughput sequencing (ATAC-seq). Tissues were collected on SD28 and LD7 conditions for RNA sequencing (RNA-seq). SD28, feed for 28 days under short-day conditions (6 h light, 18 h dark); LD3, continued providing for 3 days after conversion to long light conditions (20 h light, 4 h dark); LD7, continued feeding for 7 days after conversion to long light conditions; LD28, continued feeding for 28 days after conversion to long-day conditions. A Induction of the seasonal activation of the HPG axis by artificial photoperiod in quails. B Local T3 concentration of mediobasal hypothalamic between quails maintains underlying SD28 and LD28. C Transmission Electron microscopic images of the median hypothalamic eminence of male quail during four stages of HPG axis activity. (SD28 corresponds to 28 days under short-day conditions. LD3, LD7, and LD28 correspond to different days of conversion to long-day conditions, respectively)