Cold stress selectively unsilences tandem repeats in heterochromatin associated with accumulation of H3K9ac
Cold stress selectively unsilences tandem repeats in heterochromatin associated with accumulation of H3K9ac
复制标题
冷应激选择性地使与 H3K9ac 积累相关的异染色质中的串联重复序列沉默
DOI：
10.1111/j.1365-3040.2012.02541.x
复制
发表时间：
2012-12-01
影响因子：
7.3
通讯作者：
Li, Lijia
中科院分区：
文献类型：
--
作者：
Hu, Yong;Zhang, Lu;Li, Lijia
旋钮是细胞学上可观察到的存在于玉米细胞核上的主要间质异染色质，其由总是沉默的高度串联重复元件组成。在这里，我们研究了全基因组范围内的变化H3 K9 ac，一个活跃的染色质标记，在冷胁迫过程中使用染色质免疫沉淀测序（ChIP-Seq），并确定了差异冷诱导的H3 K9 ac富集在玉米重复序列。两个knob相关的串联重复序列，180-bp和TR-1，更详细的分析表明，冷激活其转录，这种冷诱导的转录激活的重复序列是选择性的，短暂的，并与增加H3 K9 ac和减少DNA甲基化和H3 K9 me 2。此外，结序列表达伴随着局部染色质重塑，并且沉默在长期治疗后恢复。此外，没有证据表明这些重复元件的拷贝数变化和重排被发现在植物受到冷胁迫。这些结果表明，冷介导的异染色质串联重复序列的非沉默，伴随着表观遗传调控，可能在植物适应冷刺激中发挥重要作用。
Knobs are cytologically observable major interstitial heterochromatin present on maize nuclei, which consist of highly tandem-repetitive elements that are always silenced. Here we investigated the genome-wide change of H3K9ac, an active chromatin mark, during cold stress using chromatin immunoprecipitation sequencing (ChIP-Seq) and identified differential cold-induced H3K9ac enrichment at repetitive sequences in maize. More detailed analysis of two knob-associated tandem-repetitive sequences, 180-bp and TR-1, demonstrated that cold activated their transcription and this cold-induced transcriptional activation of repetitive sequences is selective, transient, and associated with an increase in H3K9ac and a reduction in DNA methylation and H3K9me2. Furthermore, knob sequence expression is accompanied by localized chromatin remodelling and silencing is recovered upon prolonged treatment. In addition, no evidence of copy number change and rearrangement of these repetitive elements are found in plants subjected to cold stress. These results suggest that cold-mediated unsilencing of heterochromatic tandem-repeated sequences, accompanied with epigenetic regulation, might play an important role in the adaptation of plants to cold stimuli.