Liu Lingling, Wang Jin, Wang Shenghua, Wang Mudi, Chen Yuanhua, Zheng Liming
School of Basic Medical Sciences, Anhui Medical University, Hefei, China.
Front Physiol. 2022 Feb 11;13:843825. doi: 10.3389/fphys.2022.843825. eCollection 2022.
Spermatogonia are the source of spermatogenic waves. Abnormal spermatogonia can cause ab-normal spermatogenic waves, which manifest as spermatogenic disorders such as oligospermia, hypospermia, and azoospermia. Among them, the self-renewal of spermatogonia serves as the basis for maintaining the process of spermatogenesis, and the closely regulated balance between self-renewal and differentiation of spermatogonia can maintain the continuous production of spermatozoa. Tet methylcytosine dioxygenase 1(TET1) is an important epitope modifying enzyme that catalyzes the conversion of 5-methylcytosine (5-mC) to 5-hydroxymethylcytosine (5-hmC), thereby causing the methylation of specific genes site hydroxylation, enabling the DNA de-methylation process, and regulating gene expression. However, the hydroxymethylation sites at which TET1 acts specifically and the mechanisms of interaction affecting key differential genes are not clear. In the present study, we provide evidence that the expression of PLZF, a marker gene for spermatogonia self-renewal, was significantly elevated in the TET1 overexpression group, while the expression of PCNA, a proliferation-related marker gene, was also elevated at the mRNA level. Significant differential expression of SP1 was found by sequencing. SP1 expression was increased at both mRNA level and protein level after TET1 overexpression, while differential gene DAXX expression was downregulated at protein level, while the expression of its reciprocal protein P53 was upregulated. In conclusion, our results suggest that TET1 overexpression causes changes in the expression of SP1, DAXX and other genes, and that there is a certain antagonistic effect between SP1 and DAXX, which eventually reaches a dynamic balance to maintain the self-renewal state of spermatogonia for sustained sperm production. These findings may contribute to the understanding of male reproductive system disorders.
精原细胞是生精波的来源。异常的精原细胞会导致异常的生精波，表现为少精子症、弱精子症和无精子症等生精障碍。其中，精原细胞的自我更新是维持生精过程的基础，精原细胞自我更新与分化之间严格调控的平衡能够维持精子的持续产生。四甲基胞嘧啶双加氧酶1（TET1）是一种重要的表位修饰酶，它催化5-甲基胞嘧啶（5-mC）转化为5-羟甲基胞嘧啶（5-hmC），从而导致特定基因位点的甲基化羟基化，实现DNA去甲基化过程，并调节基因表达。然而，TET1具体作用的羟甲基化位点以及影响关键差异基因的相互作用机制尚不清楚。在本研究中，我们提供的证据表明，精原细胞自我更新的标记基因PLZF在TET1过表达组中的表达显著升高，而增殖相关标记基因PCNA的表达在mRNA水平也有所升高。通过测序发现SP1存在显著差异表达。TET1过表达后，SP1在mRNA水平和蛋白质水平均升高，而差异基因DAXX在蛋白质水平下调，其相互作用蛋白P53的表达上调。总之，我们的结果表明，TET1过表达导致SP1、DAXX等基因表达发生变化，且SP1与DAXX之间存在一定的拮抗作用，最终达到动态平衡以维持精原细胞的自我更新状态从而持续产生精子。这些发现可能有助于理解男性生殖系统疾病。
