MOE Key Laboratory of Biosystems Homeostasis and Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Cancer Center, Zhejiang University, Hangzhou 310058, China.
Int J Mol Sci. 2024 Jan 29;25(3):1660. doi: 10.3390/ijms25031660.
is an extremophilic microorganism that possesses a unique DNA damage repair system, conferring a strong resistance to radiation, desiccation, oxidative stress, and chemical damage. Recently, we discovered that possesses an N4-methylation (m4C) methyltransferase called M.DraR1, which recognizes the 5'-CCGCGG-3' sequence and methylates the second cytosine. Here, we revealed its cognate restriction endonuclease R.DraR1 and recognized that it is the only endonuclease specially for non-4C-methylated 5'-CCGCGG-3' sequence so far. We designated the particular m4C - as the DraI R-M system. Bioinformatics searches displayed the rarity of the DraI R-M homologous system. Meanwhile, recombination and transformation efficiency experiments demonstrated the important role of the DraI R-M system in response to oxidative stress. In addition, in vitro activity experiments showed that R.DraR1 could exceptionally cleave DNA substrates with a m5C-methlated 5'-CCGCGG-3' sequence instead of its routine activity, suggesting that this particular R-M component possesses a broader substrate choice. Furthermore, an imbalance of the DraI R-M system led to cell death through regulating genes involved in the maintenance of cell survival such as genome stability, transporter, and energy production. Thus, our research revealed a novel m4C R-M system that plays key roles in maintaining cell viability and defending foreign DNA in .
是一种极端微生物，拥有独特的 DNA 损伤修复系统，使其具有很强的辐射、干燥、氧化应激和化学损伤抗性。最近，我们发现 拥有一种名为 M.DraR1 的 N4-甲基化（m4C）甲基转移酶，它识别 5'-CCGCGG-3'序列并甲基化第二个胞嘧啶。在这里，我们揭示了其同源限制内切酶 R.DraR1，并认识到它是迄今为止唯一专门针对非 4C-甲基化 5'-CCGCGG-3'序列的内切酶。我们将特定的 m4C 命名为 DraI R-M 系统。生物信息学搜索显示，DraI R-M 同源系统非常罕见。同时，重组和转化效率实验表明，DraI R-M 系统在应对氧化应激方面起着重要作用。此外，体外活性实验表明，R.DraR1 可以异常切割具有 m5C 甲基化 5'-CCGCGG-3'序列的 DNA 底物，而不是其常规活性，这表明该特定的 R-M 组件具有更广泛的底物选择。此外，DraI R-M 系统的失衡通过调节与维持细胞存活相关的基因（如基因组稳定性、转运蛋白和能量产生）导致细胞死亡。因此，我们的研究揭示了一种新的 m4C R-M 系统，它在维持细胞活力和抵御 中的外来 DNA 方面发挥着关键作用。
