Protein arginine methyltransferase 3 fine-tunes the assembly/disassembly of pre-ribosomes to repress nucleolar stress by interacting with RPS2B in arabidopsis
Protein arginine methyltransferase 3 fine-tunes the assembly/disassembly of pre-ribosomes to repress nucleolar stress by interacting with RPS2B in arabidopsis
复制标题
拟南芥中蛋白质精氨酸甲基转移酶 3 通过与 RPS2B 相互作用来微调前核糖体的组装/分解以抑制核仁应激
DOI：
10.1016/j.molp.2020.10.006
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发表时间：
2021-02-01
期刊：
影响因子：
27.5
通讯作者：
Cao, Xiaofeng
中科院分区：
文献类型：
--
作者：
Hang, Runlai;Wang, Zhen;Cao, Xiaofeng
核糖体生物发生主要发生在核仁中，涉及前核糖体RNA（pre-rRNA）和核糖体蛋白质的协调表达、前rRNA加工以及借助于许多组装因子的亚基组装。我们以前的研究表明，拟南芥蛋白质精氨酸甲基转移酶AtPRMT 3调节前rRNA加工;然而，潜在的分子机制仍然未知。在这里，我们报告AtPRMT 3与核糖体蛋白S2（RPS 2）相互作用，促进90 S/小亚基（SSU）加工体的加工和抑制核仁应激。我们分离了一个atprmt 3 -2的基因内抑制子，它挽救了atprmt 3 -2的发育缺陷，同时产生了一个假定的截短的AtPRMT 3蛋白，该蛋白具有整个N-末端，但缺乏一个完整的酶活性结构域。我们进一步鉴定了RPS 2作为AtPRMT 3的相互作用伴侣，并发现功能丧失的rps 2a 2b突变体在表型上令人联想到atprmt 3，显示出多效性发育缺陷和异常的前rRNA加工。RPS 2B直接与细胞核中的前体rRNA结合，并且这种结合在atprmt 3 -2中增强。一致地，atprmt 3 -2中的RPS 2B更多地富集了90 S/SSU加工组的多种成分，这解释了早期前rRNA加工缺陷并导致核仁应激。总的来说，我们的研究揭示了一种新的机制，AtPRMT 3与RPS 2B合作，以促进动态组装/拆卸的90 S/SSU处理体在核糖体生物合成和抑制核仁应力。
Ribosome biogenesis, which takes place mainly in the nucleolus, involves coordinated expression of pre-ribosomal RNAs (pre-rRNAs) and ribosomal proteins, pre-rRNA processing, and subunit assembly with the aid of numerous assembly factors. Our previous study showed that the Arabidopsis thaliana protein arginine methyltransferase AtPRMT3 regulates pre-rRNA processing; however, the underlying molecular mechanism remains unknown. Here, we report that AtPRMT3 interacts with Ribosomal Protein S2 (RPS2), facilitating processing of the 90S/Small Subunit (SSU) processome and repressing nucleolar stress. We isolated an intragenic suppressor of atprmt3-2, which rescues the developmental defects of atprmt3-2 while produces a putative truncated AtPRMT3 protein bearing the entire N-terminus but lacking an intact enzymatic activity domain We further identified RPS2 as an interacting partner of AtPRMT3, and found that loss-of-function rps2a2b mutants were phenotypically reminiscent of atprmt3, showing pleiotropic developmental defects and aberrant pre-rRNA processing. RPS2B binds directly to pre-rRNAs in the nucleus, and such binding is enhanced in atprmt3-2. Consistently, multiple components of the 90S/SSU processome were more enriched by RPS2B in atprmt3-2, which accounts for early pre-rRNA processing defects and results in nucleolar stress. Collectively, our study uncovered a novel mechanism by which AtPRMT3 cooperates with RPS2B to facilitate the dynamic assembly/disassembly of the 90S/SSU processome during ribosome biogenesis and repress nucleolar stress.