近日,湖北洪山實驗室、作物遺傳改良國家重點實驗室周道繡教授課題組在The Plant Cell雜誌線上發表題為“SnRK1 stimulates the histone H3K27me3 demethylase JMJ705 to regulate a transcriptional switch to control energy homeostasis”的研究論文,揭示了組蛋白去甲基化酶JMJ705參與水稻能量穩態調節的相關表觀遺傳學機制。
能量穩態對於所有生命都至關重要。與動物相比,植物需要更為複雜的適應機制以應對不斷變化的環境,而能量穩態調節作為環境適應最為重要的一環,涉及到非常複雜的調控通路。真核生物含有一類在進化上極其保守的激酶複合體SNF1,其在能量穩態的調節中扮演著覈心調控因數的角色,這類激酶在植物中被稱之為SnRK1。SnRK1一般通過對其他蛋白進行磷酸化修飾來進行能量相關訊號的傳導與調控。當能量供應不足時,SnRK1可以調節相關基因的轉錄來促進植物能量生成,降低能量消耗以維持能量供需平衡。早期研究發現SnRK1可以直接結合染色質,然而SnRK1如何作用於染色質,進而參與基因表達的調控機制仍不清楚。
本研究發現,當水稻處於饑餓狀態時,饑餓訊號促使SnRK1在細胞核中富集,與組蛋白H3K27me3去甲基化酶JMJ705發生相互作用,並對JMJ705進行磷酸化修飾,提高其去除H3K27me3修飾的能力,降低饑餓應答基因座位上的H3K27me3修飾水准,從而促進這些基因的表達,維持細胞中足够的能量供應;在能量充足的情况下,SnRK1與JMJ705協同抑制饑餓誘導基因的表達,减少植物對能量的消耗以保證正常生長發育。本研究鑒定的SnRK1-JMJ705通路在植物細胞能量調節、染色質修飾以及基因表達調控之間建立起了直接的聯系,加深了人們對作物生長發育與逆境應答之間平衡關係的認識,對於提高作物產量與環境適應性研究有重要的啟發意義。
華中農業大學生命科學技術學院、作物遺傳改良國家重點實驗室和湖北洪山實驗室周道繡教授課題組博士生王文韜作為該文第一作者,周道繡教授為文章通訊作者,趙毓教授也參與了本研究。本研究得到國家自然科學基金重點專案“水稻能量穩態調控相關的錶觀遺傳調控機制研究”的支持,是該項目框架下的第4篇研究論文,其它三篇分別是Zhang et al.,(2017)Nuclear Acids Research;Lu et al.,(2018)Genome Biology;Xu et al.,(2021)Nuclear Acid Research。
【英文摘要】
Plant SNF1-Related Kinase1(SnRK1)is an evolutionarily conserved energy sensing protein kinase that orchestrates transcriptional networks to maintain cellular energy homeostasis when energy supplies become limited.However,the mechanism by which SnRK1 regulates this gene expression switch to gauge cellular energy status remains largely unclear.In this work,we show that the rice histone H3K27me3 demethylase JMJ705 is required for low energy stress tolerance in rice plants.The genetic inactivation of JMJ705 resulted in similar effects as those of the ricesnrk1mutant on the transcriptome,which impair not only the promotion of the low energy stress-triggered transcriptional program but also the repression of the program under an energy-sufficient state.We show that theα−subunit of OsSnRK1 interacts with and phosphorylates JMJ705 to stimulate its H3K27me3 demethylase activity.Further analysis revealed that JMJ705 directly targets a set of low energy stress-responsive transcription factor genes.These results uncover the chromatin mechanism of SnRK1-regulated gene expression in both energy-sufficient and -limited states in plants and suggest that JMJ705 functions as an upstream regulator of the SnRK1α-controlled transcriptional network.
原文連結:
https://academic.oup.com/plcell/advance-article/doi/10.1093/plcell/koab224/6366557
相關文章連結:
https://academic.oup.com/nar/article/45/21/12241/4157412
https://genomebiology.biomedcentral.com/articles/10.1186/s13059-018-1533-y
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