Xu Guanghui, Law Julie A
Plant Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA. Electronic address: https://twitter.com/@GuanghuiXu1.
Plant Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA; Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
Curr Opin Genet Dev. 2024 Feb;84:102147. doi: 10.1016/j.gde.2023.102147. Epub 2024 Jan 4.
DNA methylation is a conserved epigenetic modification associated with transposon silencing and gene regulation. The stability of this modification relies on intimate connections between DNA and histone modifications that generate self-reinforcing loops wherein the presence of one mark promotes the other. However, it is becoming increasingly clear that the efficiency of these loops is affected by cross-talk between pathways and by chromatin accessibility, which is heavily influenced by histone variants. Focusing primarily on plants, this review provides an update on the aforementioned self-reinforcing loops, highlights recent advances in understanding how DNA methylation pathways are restricted to prevent encroachment on genes, and discusses the roles of histone variants in compartmentalizing epigenetic pathways within the genome. This multilayered approach facilitates two essential, yet opposing functions, the ability to maintain heritable DNA methylation patterns while retaining the flexibility to modify these patterns during development.
DNA甲基化是一种保守的表观遗传修饰，与转座子沉默和基因调控相关。这种修饰的稳定性依赖于DNA与组蛋白修饰之间的紧密联系，这些修饰形成了自我强化的环路，其中一种标记的存在会促进另一种标记的出现。然而，越来越清楚的是，这些环路的效率受到不同途径之间的相互作用以及染色质可及性的影响，而染色质可及性又受到组蛋白变体的严重影响。本综述主要聚焦于植物，对上述自我强化环路进行了更新，强调了在理解DNA甲基化途径如何受到限制以防止对基因的侵犯方面的最新进展，并讨论了组蛋白变体在基因组内划分表观遗传途径中的作用。这种多层次的方法促进了两种基本但相反的功能，即维持可遗传的DNA甲基化模式的能力，同时在发育过程中保留修改这些模式的灵活性。
