Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA.
Curr Opin Genet Dev. 2012 Apr;22(2):132-8. doi: 10.1016/j.gde.2012.01.007. Epub 2012 Feb 13.
Accumulating evidence points toward diverse functions for plant chromatin. Remarkable progress has been made over the last few years in elucidating the mechanisms for a number of these functions. Activity of the histone demethylase IBM1 accurately targets DNA methylation to silent repeats and transposable elements, not to genes. A genetic screen uncovered the surprising role of H2A.Z-containing nucleosomes in sensing precise differences in ambient temperature and consequent gene regulation. Precise maintenance of chromosome number is assured by a histone modification that suppresses inappropriate DNA replication and by centromeric histone H3 regulation of chromosome segregation. Histones and noncoding RNAs regulate FLOWERING LOCUS C, the expression of which quantitatively measures the duration of cold exposure, functioning as memory of winter. These findings are a testament to the power of using plants to research chromatin organization, and demonstrate examples of how chromatin functions to achieve biological accuracy, precision, and memory.
越来越多的证据表明植物染色质具有多种功能。在过去的几年中，人们在阐明许多这些功能的机制方面取得了显著的进展。组蛋白去甲基酶 IBM1 的活性可以将 DNA 甲基化准确地靶向到沉默的重复序列和转座元件，而不是基因。一项遗传筛选揭示了富含 H2A.Z 的核小体在感知环境温度的精确差异和随后的基因调控方面的惊人作用。通过一种抑制不适当的 DNA 复制的组蛋白修饰和着丝粒组蛋白 H3 对染色体分离的调控，确保了染色体数目的精确维持。组蛋白和非编码 RNA 调节开花时间 LOCUS C 的表达，其表达定量衡量了寒冷暴露的持续时间，作为冬季的记忆。这些发现证明了利用植物研究染色质组织的强大功能，并展示了染色质如何发挥作用以实现生物学的准确性、精确性和记忆性。
