Jones Ashley L, Sung Sibum
Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA.
Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA
Integr Comp Biol. 2014 Jul;54(1):61-7. doi: 10.1093/icb/icu030. Epub 2014 May 7.
In plants, epigenetic regulation mediates both the proper development of the plant and responses to environmental cues. Changes in epigenetic states employ DNA methylation, histone modification, and regulatory RNAs. In Arabidopsis thaliana, DNA methylation as a repressive mark is often associated with constitutively silenced loci, such as repetitive sequences, transposons, and heterochromatin. These sequences regularly give rise to small interfering RNAs, which direct DNA methylation through the RNA-directed DNA methylation (RdDM) pathway. For example, FWA locus is silenced in sporophytes and enriched with DNA methylation. Its methylated state is stable and passes to the next generation. This is an example of meiotically inherited epigenetic states. There are also epigenetic changes that can be inherited mitotically and are subsequently erased in the next generation. In this review, we use the vernalization-mediated epigenetic silencing of FLOWERING LOCUS C (FLC) as an example for this type of mitotically stable epigenetic state. Here, we discuss mechanisms of epigenetic changes that can result in meiotically or mitotically stable states with an emphasis on FWA and FLC as two examples.
在植物中，表观遗传调控介导植物的正常发育以及对环境信号的响应。表观遗传状态的改变涉及DNA甲基化、组蛋白修饰和调控RNA。在拟南芥中，作为一种抑制标记的DNA甲基化通常与组成型沉默位点相关，如重复序列、转座子和异染色质。这些序列经常产生小干扰RNA，其通过RNA指导的DNA甲基化（RdDM）途径指导DNA甲基化。例如，FWA基因座在孢子体中沉默并富含DNA甲基化。其甲基化状态稳定并传递给下一代。这是减数分裂遗传表观遗传状态的一个例子。也存在可通过有丝分裂遗传并随后在下一代中消除的表观遗传变化。在本综述中，我们以开花位点C（FLC）的春化介导的表观遗传沉默为例来说明这种有丝分裂稳定的表观遗传状态。在此，我们讨论可导致减数分裂或有丝分裂稳定状态的表观遗传变化机制，重点以FWA和FLC为例。
