Fig. 1

Transcription and Histone Acetylation Dynamics during the Process of Follicle Growth and Ovulation. A Depiction of the controlled ovarian hyperstimulation protocol in a mouse. Immature female mice were primed with pregnant mare chorionic gonadotropin (PMSG) to stimulate follicular growth, followed by injection with human chorionic gonadotropin (hCG) 48 h later to induce ovulation. At the indicated timepoints, the ovaries were collected for analysis. P0, P24, H0: 0 h, 24 h, and 48 h after PMSG treatment. H1-8: 1 h, 2 h, 4 h, and 8 h after hCG treatment, equal to LH surge. The arrowheads indicate two types of granulosa cells (GCs) in the antral follicle. B The levels of transcription and histone acetylation were dramatically downregulated between the two surges mediated by PMSG and hCG. The ovaries at the indicated timepoints were collected and lysed for Western blotting with antibodies against phosphorylated RNA polymerase CTD S2 (pPol II(S2)), H3K27Ac, H4K16Ac, H3K9Ac, and histone H3. C Quantitative analysis of pPol II(S2), H3K27Ac, H4K16Ac, and H3K9Ac levels with histone H3 normalization in panel B using the ImageJ software. The data were expressed as the mean ± SD. P value was determined by two-way ANOVA, followed by Tukey’s post-test. *P < 0.05, **P < 0.01. D, E The immunofluorescence results exhibiting the dynamics of pPol II (S2) (D, red) and H3K27Ac (E, red) in ovarian antral follicles at the indicated timepoints post-PMSG or/and hCG treatment. The nuclei were stained with DAPI (blue). Scale bar = 100 μm. N = 3 biologically independent experiments