Chatti Abdelwaheb, Landoulsi Ahmed
Unité de biochimie des lipides et interaction des macromolécules en biologie, 03/UR/0902, faculté des sciences de Bizerte, Zarzouna 7021, Tunisie.
C R Biol. 2008 Sep;331(9):648-54. doi: 10.1016/j.crvi.2008.06.002. Epub 2008 Jul 2.
The DNA methylation is a post-replicative event that provides secondary information to that formed by DNA. Addition of this information involves DAM methyltransferase, which methylates DNA on specific sites (5'-GATC-3'). This modification of DNA may play a role in regulating various processes in eukaryote or prokaryote cells. It was well understood that deoxyadenosine methyltransferase (DAM) methylates the adenine of the GATC sequence. Following DNA replication, however, DNA is transiently hemimethylated, and the new strand is then methylated by DAM. In Escherichia coli, removing the dam gene produces several phenotypes indicating multiple functions of methylation: (i) modulation of gene expression, (ii) DNA repair, (iii) initiation of replication, and (iv) stabilising the chromosome.
DNA甲基化是一种复制后事件，它为DNA形成的信息提供了二级信息。这种信息的添加涉及DAM甲基转移酶，该酶会在特定位点（5'-GATC-3'）使DNA甲基化。DNA的这种修饰可能在真核细胞或原核细胞中调节各种过程中发挥作用。人们很清楚脱氧腺苷甲基转移酶（DAM）会使GATC序列中的腺嘌呤甲基化。然而，在DNA复制之后，DNA会暂时处于半甲基化状态，然后新链会被DAM甲基化。在大肠杆菌中，去除dam基因会产生几种表型，表明甲基化具有多种功能：（i）基因表达的调节，（ii）DNA修复，（iii）复制起始，以及（iv）稳定染色体。
