环境因素对DNA甲基化的影响

摘要

DNA methylation is catalyzed by a family of DNA methyltransferases (DNMTs) that transfer a methyl group from S-adenyl methionine (SAM) to the fifth carbon of a cytosine residue to form 5mC.DNA methylation affects the interaction between the histone and DNA,which changes the chromosome structure and has reverse relationship with gene expression in general.Up to now,more and more studies have confirmed that environmental factors can alter epigenetic modifications,which do not involve in changing DNA sequence.So it can explain the phenotype of creature in a certain degree.This article focused on the influence of environmental factors,such as temperature,nutrient supply,heavy metal,early stress and radiation,on DNA methylation change.As a matter of fact,it does not only change the DNA methylation in parents and offspring but also their behavior and phenotype.Overall,this review will help us get better understanding of the relationship between environmental factors and gene expression regulation.%在哺乳动物中,DNA甲基化是指在DNA甲基转移酶(DNA-methyl transferase,DNMT)的作用下,以S-腺苷甲硫氨酸提供甲基供体,将其甲基转移到脱氧胞嘧啶环第5位碳原子形成甲基化脱氧胞嘧啶的共价修饰.DNA甲基化改变组蛋白和DNA之间的相互作用,使染色质构象发生改变从而影响基因的表达,总体来说DNA甲基化水平与基因的表达呈负相关.越来越多的报道证实,环境因素可以影响表观遗传修饰,其并没有涉及遗传信息的改变,所以在一定范围内可以解释表型变化.文章围绕环境因素(温度、营养供给、异常化学因子、早期环境刺激和辐射等)对DNA甲基化产生的影响进行综述,这些影响包括亲代和子代DNA甲基化的改变及子代行为和表型变化等方面,以期进一步阐释环境因素与基因互作的关系.