The ribosome assembly factor Nop53 controls association of the RNA exosome with pre-60S particles in yeast
The ribosome assembly factor Nop53 controls association of the RNA exosome with pre-60S particles in yeast
复制标题
核糖体组装因子 Nop53 控制酵母中 RNA 外泌体与前 60S 颗粒的关联
DOI：
10.1074/jbc.ra119.010193
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发表时间：
2019-12-13
影响因子：
4.8
通讯作者：
Oliveira, Carla C.
中科院分区：
文献类型：
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作者：
Cepeda, Leidy Paola P.;Bagatelli, Felipe F. M.;Oliveira, Carla C.
真核生物核糖体的生物发生是一个高度耗能和复杂的过程，需要数百个反式作用因子来动态构建高度组织化的40S和60S亚基。每个核糖核蛋白复合体由特定的rRNA和核糖体蛋白组成，它们被组织成功能结构域。RNA外体复合体作为60S前加工因子之一起着至关重要的作用，因为它是负责将7S前rRNA加工成成熟的5.8S rRNA的核糖核酸酶。酵母Pre-60S组装因子Nop53先前已被证明与核质Pre-60s相关，该区域包含围绕7S Pre-rRNA的3‘端组装的“脚”结构。Nop53与25S rRNA和几个60S组装因子相互作用，包括RNA外体，特别是与其催化亚基RRP6和外体相关的RNA解旋酶MTR4。因此，NOP53被认为是负责招募外体复合体进行7S加工的接头。在这里，使用基于蛋白质组学的方法在萌芽酵母中分析Nop53对外糖体相互作用组的影响，我们发现外糖体在核糖体成熟途径的早期与核糖体前复合体结合。我们还发现了Nop53在60S成熟背景下调控外切体活性的相互作用，并提供了证据表明，除了招募外切体外，Nop53可能在7S加工过程中对外切体的定位也很重要。在这些发现的基础上，我们提出，在核糖体组装过程中，外切糖体被招募的时间比之前认为的要早得多，这表明存在其他有待描述的相互作用。
Eukaryotic ribosomal biogenesis is a highly energy-demanding and complex process that requires hundreds of trans-acting factors to dynamically build the highly organized 40S and 60S subunits. Each ribonucleoprotein complex comprises specific rRNAs and ribosomal proteins that are organized into functional domains. The RNA exosome complex plays a crucial role as one of the pre-60S-processing factors, because it is the RNase responsible for processing the 7S pre-rRNA to the mature 5.8S rRNA. The yeast pre-60S assembly factor Nop53 has previously been shown to associate with the nucleoplasmic pre-60S in a region containing the "foot" structure assembled around the 3' end of the 7S pre-rRNA. Nop53 interacts with 25S rRNA and with several 60S assembly factors, including the RNA exosome, specifically, with its catalytic subunit Rrp6 and with the exosome-associated RNA helicase Mtr4. Nop53 is therefore considered the adaptor responsible for recruiting the exosome complex for 7S processing. Here, using proteomics-based approaches in budding yeast to analyze the effects of Nop53 on the exosome interactome, we found that the exosome binds pre-ribosomal complexes early during the ribosome maturation pathway. We also identified interactions through which Nop53 modulates exosome activity in the context of 60S maturation and provide evidence that in addition to recruiting the exosome, Nop53 may also be important for positioning the exosome during 7S processing. On the basis of these findings, we propose that the exosome is recruited much earlier during ribosome assembly than previously thought, suggesting the existence of additional interactions that remain to be described.