Selective Cleavage at CCA Ends and Anticodon Loops of tRNAs by Stress-Induced RNases.
Selective Cleavage at CCA Ends and Anticodon Loops of tRNAs by Stress-Induced RNases.
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DOI：
10.3389/fmolb.2022.791094
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发表时间：
2022
影响因子：
5
通讯作者：
Ivanov P
中科院分区：
文献类型：
--
作者：
Akiyama Y;Lyons SM;Fay MM;Tomioka Y;Abe T;Anderson PJ;Ivanov P
应激诱导的tRNA切割涉及多种细胞过程，其中tRNA片段发挥不同的调节作用。血管生成素（ANG）是RNA酶A超家族的成员，其诱导tRNA的切割，导致tRNA衍生的应激诱导RNA（tiRNA）的形成，其有助于旨在细胞存活的翻译重编程。除了切割tRNA反密码子环外，ANG在体外还能切割tRNA的3′-CCA末端，尽管尚不清楚该过程是否发生在细胞中。也有人提出，tiRNAs可以独立于ANG产生，尽管对其他应激诱导的RNA酶在tRNA切割中的作用知之甚少。使用基因编辑和生物化学方法，我们通过关注其对CCA末端和反密码子环的切割，研究了ANG在应激诱导的tRNA切割中的参与。我们发现ANG对亚砷酸钠（SA）处理的细胞中的CCA失活没有影响，尽管ANG处理显著增加了细胞中的3′-tiRNA水平，但大多数3′-tiRNA保留了它们的3′-CCA末端。相反，其他RNA酶可以切割细胞中的CCA末端，尽管效率较低。此外，在不存在ANG的情况下，其他RNA酶能够促进细胞中tiRNA的产生。RNH 1（RNase A超家族的内源性抑制剂）的消耗促进细胞中组成型产生的tiRNAs和CCA失活的tRNA。有趣的是，SA处理RNH 1耗尽的细胞中的tiRNAs或CCA失活的tRNA的量没有增加，这表明RNA酶A超家族酶在很大程度上负责SA诱导的tRNA切割。我们发现，压力诱导的RNases之间的相互作用导致靶向tRNA在细胞中的压力特异性的方式。
Stress-induced tRNA cleavage has been implicated in various cellular processes, where tRNA fragments play diverse regulatory roles. Angiogenin (ANG), a member of the RNase A superfamily, induces cleavage of tRNAs resulting in the formation of tRNA-derived stress-induced RNAs (tiRNAs) that contribute to translational reprogramming aiming at cell survival. In addition to cleaving tRNA anticodon loops, ANG has been shown to cleave 3′-CCA termini of tRNAs in vitro, although it is not known whether this process occurs in cells. It has also been suggested that tiRNAs can be generated independently of ANG, although the role of other stress-induced RNases in tRNA cleavage is poorly understood. Using gene editing and biochemical approaches, we examined the involvement of ANG in stress-induced tRNA cleavage by focusing on its cleavage of CCA-termini as well as anticodon loops. We show that ANG is not responsible for CCA-deactivation under sodium arsenite (SA) treatment in cellulo, and although ANG treatment significantly increases 3′-tiRNA levels in cells, the majority of 3′-tiRNAs retain their 3′-CCA termini. Instead, other RNases can cleave CCA-termini in cells, although with low efficiency. Moreover, in the absence of ANG, other RNases are able to promote the production of tiRNAs in cells. Depletion of RNH1 (an endogenous inhibitor of RNase A superfamily) promotes constitutively-produced tiRNAs and CCA-deactivated tRNAs in cells. Interestingly, SA treatment in RNH1-depleted cells did not increase the amount of tiRNAs or CCA-deactivated tRNAs, suggesting that RNase A superfamily enzymes are largely responsible for SA-induced tRNA cleavage. We show that interplay between stress-induced RNases cause targeting tRNAs in a stress-specific manner in cellulo.