Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, 1030 Viena, Austria.
Plant Cell. 2010 Jan;22(1):34-47. doi: 10.1105/tpc.109.072819. Epub 2010 Jan 22.
Epigenetic changes of gene expression can potentially be reversed by developmental programs, genetic manipulation, or pharmacological interference. However, a case of transcriptional gene silencing, originally observed in tetraploid Arabidopsis thaliana plants, created an epiallele resistant to many mutations or inhibitor treatments that activate many other suppressed genes. This raised the question about the molecular basis of this extreme stability. A combination of forward and reverse genetics and drug application provides evidence for an epigenetic double lock that is only alleviated upon the simultaneous removal of both DNA methylation and histone methylation. Therefore, the cooperation of multiple chromatin modifications can generate unanticipated stability of epigenetic states and contributes to heritable diversity of gene expression patterns.
基因表达的表观遗传变化可能会被发育程序、遗传操作或药物干预所逆转。然而，最初在四倍体拟南芥植物中观察到的转录基因沉默现象，产生了一个对抗许多突变或抑制剂处理的表观等位基因，这些处理会激活许多其他被抑制的基因。这就提出了一个问题，即这种极端稳定性的分子基础是什么。正向和反向遗传学以及药物应用的结合为一种表观遗传双锁提供了证据，只有当 DNA 甲基化和组蛋白甲基化同时被去除时，这种双锁才会被缓解。因此，多种染色质修饰的协同作用可以产生意想不到的表观遗传状态稳定性，并有助于基因表达模式的可遗传性多样性。
