Ethyl methanesulfonate (EMS) is a monofunctional ethylating agent that has been found to be mutagenic in a wide variety of genetic test systems from viruses to mammals. It has also been shown to be carcinogenic in mammals. Alkylation of cellular, nucleophilic sites by EMS occurs via a mixed SN1/SN2 reaction mechanism. While ethylation of DNA occurs principally at nitrogen positions in the bases, because of the partial SN1 character of the reaction, EMS is also able to produce significant levels of alkylation at oxygens such as the O6 of guanine and in the DNA phosphate groups. Genetic data obtained using microorganisms suggest that EMS may produce both GC to AT and AT to GC transition mutations. There is also some evidence that EMS can cause base-pair insertions or deletions as well as more extensive intragenic deletions. In higher organisms, there is clear-cut evidence that EMS is able to break chromosomes, although the mechanisms involved are not well understood. An often cited hypothesis is that DNA bases ethylated by EMS (mostly the N-7 position of guanine) gradually hydrolyze from the deoxyribose on the DNA backbone leaving behind an apurinic (or possibly an apyrimidinic) site that is unstable and can lead to single-strand breakage of the DNA. Data also exist that suggest that ethylation of some chromosomal proteins in mouse spermatids by EMS may be an important factor in causing chromosome breakage.

中文翻译：

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甲磺酸乙酯的遗传效应综述。

甲磺酸乙酯（EMS）是一种单官能化的乙基化剂，已被发现在从病毒到哺乳动物的各种基因测试系统中均具有致突变性。它也已被证明在哺乳动物中具有致癌性。EMS通过混合的SN1 / SN2反应机制发生细胞亲核位点的烷基化。尽管DNA的乙基化主要发生在碱基的氮位置，但由于该反应的部分SN1特性，EMS也能够在鸟嘌呤的O6等氧和DNA磷酸基团上产生显着水平的烷基化。使用微生物获得的遗传数据表明，EMS可能同时产生从GC到AT的突变以及从AT到GC的突变。还有一些证据表明，EMS可以引起碱基对的插入或缺失以及更广泛的基因内缺失。在高等生物中 有明确的证据表明EMS能够破坏染色体，尽管所涉及的机制尚不十分清楚。一个经常被引用的假说是，被EMS乙基化的DNA碱基（大多数是鸟嘌呤的N-7位）从DNA骨架上的脱氧核糖逐渐水解，留下了一个不稳定的嘌呤（或可能为嘧啶二酮）位点，并可能导致单- DNA的链断裂。还存在数据表明，EMS对小鼠精子中某些染色体蛋白质的乙基化可能是导致染色体断裂的重要因素。一个经常被引用的假说是，被EMS乙基化的DNA碱基（大多数是鸟嘌呤的N-7位）从DNA骨架上的脱氧核糖逐渐水解，留下了一个不稳定的嘌呤（或可能为嘧啶二酮）位点，并可能导致单- DNA的链断裂。还存在数据表明，EMS对小鼠精子中某些染色体蛋白质的乙基化可能是导致染色体断裂的重要因素。一个经常被引用的假说是，被EMS乙基化的DNA碱基（大多数是鸟嘌呤的N-7位）从DNA骨架上的脱氧核糖逐渐水解，留下了一个不稳定的嘌呤（或可能为嘧啶二酮）位点，并可能导致单- DNA的链断裂。还存在数据表明，EMS对小鼠精子中某些染色体蛋白质的乙基化可能是导致染色体断裂的重要因素。