The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China.
Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China.
PLoS One. 2020 Oct 20;15(10):e0240844. doi: 10.1371/journal.pone.0240844. eCollection 2020.
Cruciform DNA is a causing factor of genome instability and chromosomal translocation, however, most studies about cruciform DNA in mammalian cells were based on palindromic sequences containing plasmids and reports about endogenous cruciform DNA are rare. In this study we observed the dynamics of endogenous cruciform DNA in mouse growing oocytes using immunofluorescence labeling method. We found cruciform DNA foci exist in transcription active growing oocytes but not in transcription inactive fully grown oocytes and colocalized with Parp1 but not with DNA damage marker γH2A.X. By analyzing the Genotype-Tissue Expression data, we found cruciform DNA-mediated chromosomal translocation in human spermatocytes is associated with the specific DNA transcription in testis. When inhibiting the transcription with α-amanitin in mouse oocytes, we found oocyte cruciform DNA foci decreased significantly. In summary, we observed the endogenous cruciform DNA in growing oocytes and our results showed that the cruciform DNA formation is transcription-dependent.
十字形 DNA 是基因组不稳定性和染色体易位的一个致病因素，然而，大多数关于哺乳动物细胞中十字形 DNA 的研究都是基于含有质粒的回文序列，关于内源性十字形 DNA 的报道很少。在这项研究中，我们使用免疫荧光标记法观察了小鼠生长卵母细胞中内源性十字形 DNA 的动态变化。我们发现十字形 DNA 焦点存在于转录活跃的生长卵母细胞中，但不存在于转录不活跃的完全成熟卵母细胞中，并且与 Parp1 共定位，但与 DNA 损伤标记 γH2A.X 不共定位。通过分析基因型-组织表达数据，我们发现人类精母细胞中的十字形 DNA 介导的染色体易位与睾丸中特定的 DNA 转录有关。当用α-鹅膏蕈碱在小鼠卵母细胞中抑制转录时，我们发现卵母细胞中的十字形 DNA 焦点明显减少。总之，我们观察到了生长卵母细胞中的内源性十字形 DNA，我们的结果表明，十字形 DNA 的形成是转录依赖性的。
