Department of Biology, Miami University, Oxford, OH 45056, USA.
Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA.
Curr Opin Plant Biol. 2023 Oct;75:102428. doi: 10.1016/j.pbi.2023.102428. Epub 2023 Jul 21.
Plant genomes are littered with transposable elements (TEs). Because TEs are potentially highly mutagenic, host organisms have evolved a set of defense mechanisms to recognize and epigenetically silence them. Although the maintenance of TE silencing is well studied, our understanding of the initiation of TE silencing is limited, but it clearly involves small RNAs and DNA methylation. Once TEs are silent, the silent state can be maintained to subsequent generations. However, under some circumstances, such inheritance is unstable, leading to the escape of TEs to the silencing machinery, resulting in the transcriptional activation of TEs. Epigenetic control of TEs has been found to be closely linked to many other epigenetic phenomena, such as genomic imprinting, and is known to contribute to regulation of genes, especially those near TEs. Here we review and discuss the current models of TE silencing, its unstable inheritance after hybridization, and the effects of epigenetic regulation of TEs on genomic imprinting.
植物基因组中散布着转座元件（TEs）。由于 TEs 具有潜在的高度突变性，宿主生物体已经进化出了一套防御机制来识别和表观沉默它们。尽管 TE 沉默的维持已得到很好的研究，但我们对 TE 沉默的起始的理解是有限的，但它显然涉及小 RNA 和 DNA 甲基化。一旦 TEs 沉默，沉默状态可以被维持到后代。然而，在某些情况下，这种遗传是不稳定的，导致 TEs 逃避沉默机制，导致 TEs 的转录激活。已经发现 TE 的表观遗传控制与许多其他表观遗传现象密切相关，例如基因组印记，并已知其有助于基因的调控，特别是那些靠近 TE 的基因。在这里，我们回顾和讨论 TE 沉默的当前模型、杂交后其不稳定的遗传以及 TE 的表观遗传调控对基因组印记的影响。
