Department of Histology and Embryology, Ankara Medipol University School of Medicine, Ankara, Turkey.
Ankara University Biotechnology Institute, Ankara, Turkey.
Andrologia. 2022 May;54(4):e14357. doi: 10.1111/and.14357. Epub 2022 Jan 8.
DNA methylation plays important roles during spermatogenesis. This mechanism includes maintenance and de novo methylation which are catalysed by DNA methyltransferase enzymes. DNMT1 plays role in maintenance methylation, while DNMT3A, DNMT3B and DNMT3L are primarily responsible for de novo methylation. Both maintenance and de novo methylation processes appears during primordial germ cell development and spermatogenesis. However, the function(s) of the methylation and DNMTs during spermatogenesis still remain elusive. The aim of the study was to evaluate the relationship between DNMTs levels and global DNA methylation in total testis and during spermatogenesis. For this purpose, DNMTs were analysed using Western blot and immunohistochemistry techniques. We also analysed global DNA methylation level by 5mC staining. We found that DNMTs expression and global DNA methylation levels were significantly differed in total testes and spermatogenetic cells in a stage-dependent manner. DNMT3B and DNMT3L were more abundant in testes, while DNMT1 and DNMT3A were comparatively low. Interestingly, no DNMTs signal was seen in elongated spermatid whereas global DNA methylation was at the highest level. To understand the meaning of differential expressions of DNMTs in the testes, further molecular biological studies are required.
DNA 甲基化在精子发生过程中发挥重要作用。该机制包括由 DNA 甲基转移酶酶催化的维持和从头甲基化。DNMT1 参与维持甲基化，而 DNMT3A、DNMT3B 和 DNMT3L 主要负责从头甲基化。维持和从头甲基化过程均发生在原始生殖细胞发育和精子发生过程中。然而，甲基化和 DNMTs 在精子发生过程中的功能仍不清楚。本研究旨在评估 DNMTs 水平与睾丸总组织和精子发生过程中全基因组 DNA 甲基化之间的关系。为此，我们使用 Western blot 和免疫组织化学技术分析了 DNMTs。我们还通过 5mC 染色分析了全基因组 DNA 甲基化水平。我们发现，DNMTs 的表达和全基因组 DNA 甲基化水平在睾丸和精子发生细胞中均呈现出与发育阶段相关的显著差异。DNMT3B 和 DNMT3L 在睾丸中更为丰富，而 DNMT1 和 DNMT3A 则相对较低。有趣的是，在伸长的精子中没有观察到 DNMTs 信号，而全基因组 DNA 甲基化水平达到最高。为了理解 DNMTs 在睾丸中差异表达的意义，需要进一步的分子生物学研究。
