Canonical and Noncanonical Actions of Arabidopsis Histone Deacetylases in Ribosomal RNA Processing
Canonical and Noncanonical Actions of Arabidopsis Histone Deacetylases in Ribosomal RNA Processing
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DOI：
10.1105/tpc.17.00626
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发表时间：
2018-01-01
期刊：
影响因子：
11.6
通讯作者：
Zhong, Xuehua
中科院分区：
文献类型：
--
作者：
Chen, Xiangsong;Lu, Li;Zhong, Xuehua
核糖体的生物发生是所有细胞活动所必需的一个基本过程。组蛋白去乙酰化酶在包括转录抑制和rDNA沉默在内的许多生物学过程中发挥着关键作用。然而，它们在pre-rRNA加工中的功能仍然知之甚少。在这里，我们发现拟南芥组蛋白去乙酰化酶HD2C通过规范和非规范方式在pre-rRNA加工中具有先前未被描述的作用。HD2C与另一组蛋白去乙酰化酶HD2B相互作用，在核仁中形成同源和/或异聚物。HD2C和HD2B的缺失导致核糖体生物发生缺陷表型和18S pre-rRNA中间体的异常积累。我们的全基因组分析显示，HD2C结合并抑制参与核糖体生物发生的关键基因的表达。通过RNA免疫沉淀和测序，我们进一步揭示了HD2C直接与pre-rRNA和小核仁RNA相关的非规范机制，以调节rRNA甲基化。总之，本研究揭示了HD2C在核糖体生物发生中的多方面作用，并提供了组蛋白去乙酰化酶如何在转录和转录后水平调节rRNA成熟的机制见解。
Ribosome biogenesis is a fundamental process required for all cellular activities. Histone deacetylases play critical roles in many biological processes including transcriptional repression and rDNA silencing. However, their function in pre-rRNA processing remains poorly understood. Here, we discovered a previously uncharacterized role of Arabidopsis thaliana histone deacetylase HD2C in pre-rRNA processing via both canonical and noncanonical manners. HD2C interacts with another histone deacetylase HD2B and forms homo- and/or hetero-oligomers in the nucleolus. Depletion of HD2C and HD2B induces a ribosome-biogenesis deficient phenotype and aberrant accumulation of 18S pre-rRNA intermediates. Our genome-wide analysis revealed that HD2C binds and represses the expression of key genes involved in ribosome biogenesis. Using RNA immunoprecipitation and sequencing, we further uncovered a noncanonical mechanism of HD2C directly associating with pre-rRNA and small nucleolar RNAs to regulate rRNA methylation. Together, this study reveals a multifaceted role of HD2C in ribosome biogenesis and provides mechanistic insights into how histone deacetylases modulate rRNA maturation at the transcriptional and posttranscriptional levels.