Leroux Émélie, Brosseau Cindy, Angers Bernard, Angers Annie, Breton Sophie
Département de sciences biologiques, Université de Montréal, Campus MIL, Faculté des Arts et des Sciences, CP 6128, Succursale Centre-Ville, Montréal QC, H3C 3J7, Canada.
Med Sci (Paris). 2021 Mar;37(3):258-264. doi: 10.1051/medsci/2021011. Epub 2021 Mar 19.
DNA methylation is an epigenetic mechanism that has been largely probed regarding eukaryotic nuclear genome and bacteria, and its role is especially crucial in the regulation of gene expression. In mammals, it is almost exclusively acting on a cytosine preceding a guanine (CpG), whereas it presents itself mainly in a non-CpG context in bacteria's DNA. Conversely to nuclear and bacterial genomes, the existence of methylation in the mitochondrial genome is still widely debated. This controversy has been attributed to structural differences between the nuclear and mitochondrial genomes, and to the techniques used to study methylation of cytosines, which were rather optimized for the study of nuclear DNA. However, novel studies suggest that cytosine methylation is truly existing in mitochondria, and that it is mostly found in a non-CpG context, just like in their evolutionary relative, the bacteria.
DNA甲基化是一种表观遗传机制，人们已对真核细胞核基因组和细菌进行了大量关于该机制的探究，其在基因表达调控中发挥着尤为关键的作用。在哺乳动物中，它几乎只作用于鸟嘌呤之前的胞嘧啶（CpG），而在细菌DNA中，它主要存在于非CpG环境中。与核基因组和细菌基因组相反，线粒体基因组中甲基化的存在仍存在广泛争议。这种争议归因于核基因组和线粒体基因组之间的结构差异，以及用于研究胞嘧啶甲基化的技术，这些技术在很大程度上是为研究核DNA而优化的。然而，新的研究表明，胞嘧啶甲基化确实存在于线粒体中，并且它大多存在于非CpG环境中，就像在与其具有进化关系的细菌中一样。
