School of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA.
Insect Mol Biol. 2011 Oct;20(5):553-65. doi: 10.1111/j.1365-2583.2011.01092.x. Epub 2011 Jun 24.
DNA methylation plays an important role in gene regulation in animals. However, the evolution and function of DNA methylation has only recently emerged as the subject of widespread study in insects. In this review we profile the known distribution of DNA methylation systems across insect taxa and synthesize functional inferences from studies of DNA methylation in insects and vertebrates. Unlike vertebrate genomes, which tend to be globally methylated, DNA methylation is primarily targeted to genes in insects. Nevertheless, mounting evidence suggests that a specialized role exists for genic methylation in the regulation of transcription, and possibly mRNA splicing, in both insects and mammals. Investigations in several insect taxa further reveal that DNA methylation is preferentially targeted to ubiquitously expressed genes and may play a key role in the regulation of phenotypic plasticity. We suggest that insects are particularly amenable to advancing our understanding of the biological functions of DNA methylation, because insects are evolutionarily diverse, display several lineage-specific losses of DNA methylation and possess tractable patterns of DNA methylation in moderately sized genomes.
DNA 甲基化在动物基因调控中发挥着重要作用。然而，DNA 甲基化的进化和功能直到最近才成为昆虫研究的热门课题。在这篇综述中，我们概述了已知的 DNA 甲基化系统在昆虫分类群中的分布，并综合了昆虫和脊椎动物中 DNA 甲基化研究的功能推断。与倾向于全局甲基化的脊椎动物基因组不同，DNA 甲基化主要靶向昆虫中的基因。然而，越来越多的证据表明，基因甲基化在昆虫和哺乳动物的转录调控中具有特殊的作用，可能还参与了 mRNA 剪接。在几个昆虫分类群中的研究进一步表明，DNA 甲基化优先靶向广泛表达的基因，并可能在表型可塑性的调控中发挥关键作用。我们认为，昆虫特别适合于深入了解 DNA 甲基化的生物学功能，因为昆虫在进化上具有多样性，表现出几种谱系特异性的 DNA 甲基化缺失，并在中等大小的基因组中具有可处理的 DNA 甲基化模式。
