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寒冷在拟南芥中诱导FRIGIDA核凝集物来抑制FLC
2021-11-07 13:08

英国诺里奇科研公园Caroline Dean团队发现,寒冷在拟南芥中诱导FRIGIDA核凝集物来抑制FLC。相关论文于2021年11月3日在线发表在《自然》杂志上。

研究人员表示,植物利用季节性的温度线索来确定向繁殖过渡的时间。在拟南芥中,冬季的寒冷通过POLYCOMB REPRESSIVE COMPLEX 2(PRC2)使花卉抑制位点FLOWERING LOCUS C(FLC)表观遗传沉默。这个春化过程使开花与春天一致。沉默的一个先决条件是FLC的转录下调,但在秋季波动的温度制度中如何发生,尚不清楚。转录抑制与组蛋白H3在K36处三甲基化(H3K36me3)和H3在K4处三甲基化(H3K4me3)的局部水平下降相关,在依赖FRIGIDA(FRI)激活FLC的过程中,这些三甲基化被添加。

研究人员发现,寒冷会迅速促进FRI核凝集物的形成,而这些凝集物并不与活跃的FLC基因座共存。这与FRI在FLC启动子上的占有率降低和FLC的抑制有关。温暖的温度峰值扭转了这一过程,缓冲了FLC的关闭来防止过早开花。凝集物在低温下的积累受特定共转录调节因子和反义RNA COOLAIR特定异构体的低温诱导的影响。这项工作描述了一个转录激活因子的动态分区,赋予其对自然温度波动的可塑性,从而使植物能够有效地监测季节性进展。

附:英文原文

Title: Cold-induced Arabidopsis FRIGIDA nuclear condensates for FLC repression

Author: Zhu, Pan, Lister, Clare, Dean, Caroline

Issue&Volume: 2021-11-03

Abstract: Plants use seasonal temperature cues to time the transition to reproduction. In Arabidopsis thaliana, winter cold epigenetically silences the floral repressor locus FLOWERING LOCUS C (FLC) through POLYCOMB REPRESSIVE COMPLEX 2 (PRC2)1. This vernalization process aligns flowering with spring. A prerequisite for silencing is transcriptional downregulation of FLC, but how this occurs in the fluctuating temperature regimes of autumn is unknown2,3,4. Transcriptional repression correlates with decreased local levels of histone H3 trimethylation at K36 (H3K36me3) and H3 trimethylation at K4 (H3K4me3)5,6, which are deposited during FRIGIDA (FRI)-dependent activation of FLC7,8,9,10. Here we show that cold rapidly promotes the formation of FRI nuclear condensates that do not colocalize with an active FLC locus. This correlates with reduced FRI occupancy at the FLC promoter and FLC repression. Warm temperature spikes reverse this process, buffering FLC shutdown to prevent premature flowering. The accumulation of condensates in the cold is affected by specific co-transcriptional regulators and cold induction of a specific isoform of the antisense RNA COOLAIR5,11. Our work describes the dynamic partitioning of a transcriptional activator conferring plasticity in response to natural temperature fluctuations, thus enabling plants to effectively monitor seasonal progression.

DOI: 10.1038/s41586-021-04062-5

Source: https://www.nature.com/articles/s41586-021-04062-5

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:69.504
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html


本期文章:《自然》:Online/在线发表

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