Changes in DNA Methylation of Oocytes and Granulosa Cells Assessed by HELMET during Folliculogenesis in Mouse Ovary.

In this study, we examined changes in the methylation level of CCGG and GATCG sites during mouse folliculogenesis in paraffin-embedded sections of mouse ovaries. For the purpose, we used a new method, histo endonuclease-linked detection of methylation sites of DNA (HELMET), designed to detect methylation sites of DNA with a specific sequence in a tissue section. Unlike the global level of DNA methylation, which was no change in immunohistochemical staining of 5-methylcytosine throughout folliculogenesis, we found that there were hypermethylation of CCGG and GATCG sites in most of the granulosa cells of tertiary follicles compared to that of primary and secondary follicles. Interestingly, TUNEL-positive granulosa cells, which were frequent in mammalian folliculogenesis, became markedly Hpa II-reactive and Sau3A I-reactive, indicating that the CCGG and GATCG sites may be preferentially demethylated during apoptosis.
PMID: 29867282 [PubMed]

Source: Acta Histochemica et Cytochemica - April 27, 2018 Category: Biochemistry Authors: Liu J, Zhang W, Wu Z, Dai L, Koji T Tags: Acta Histochem Cytochem Source Type: research