Evidence for autophagy-dependent pathways of rRNA turnover in Arabidopsis
Evidence for autophagy-dependent pathways of rRNA turnover in Arabidopsis
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DOI：
10.1080/15548627.2015.1106664
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发表时间：
2015-12-01
期刊：
影响因子：
13.3
通讯作者：
Bassham, Diane C.
中科院分区：
文献类型：
--
作者：
Floyd, Brice E.;Morriss, Stephanie C.;Bassham, Diane C.
核糖体占细胞RNA和蛋白质的大部分，是细胞资源的重要投资。已经提出核糖体的周转和降解在稳态和应激条件下起作用。rRNA和核糖体蛋白的周转机制尚未完全阐明。我们在这里表明，RNS 2核糖核酸酶和自噬参与RNA周转在拟南芥在正常生长条件下。在rns 2 -2突变体中观察到自噬体形成的增加，并且这种增加依赖于核心自噬基因ATG 9和ATG 5。rns 2 -2突变体中的自噬体和自噬小体含有RNA和核糖体，表明自噬被激活是为了补偿rRNA降解的损失。总RNA在rns 2 -2、atg 9 -4、atg 5 -1、rns 2 -2 atg 9 -4和rns 2 -2 atg 5 -1突变体中积累，表明自噬和RNS 2在RNA周转中的平行作用。在rns 2 -2突变体中，rRNA在液泡中积累。通过rns 2 -2 atg 5 -1双突变体破坏自噬而阻断rRNA的细胞内积累，但通过rns 2 -2 atg 9 -4双突变体不能阻断自噬，表明ATG 5和ATG 9在该过程中的功能不同。我们的研究结果表明，自噬和RNS 2都参与了液泡中rRNA的稳态降解。
Ribosomes account for a majority of the cell's RNA and much of its protein and represent a significant investment of cellular resources. The turnover and degradation of ribosomes has been proposed to play a role in homeostasis and during stress conditions. Mechanisms for the turnover of rRNA and ribosomal proteins have not been fully elucidated. We show here that the RNS2 ribonuclease and autophagy participate in RNA turnover in Arabidopsis thaliana under normal growth conditions. An increase in autophagosome formation was seen in an rns2-2 mutant, and this increase was dependent on the core autophagy genes ATG9 and ATG5. Autophagosomes and autophagic bodies in rns2-2 mutants contain RNA and ribosomes, suggesting that autophagy is activated as an attempt to compensate for loss of rRNA degradation. Total RNA accumulates in rns2-2, atg9-4, atg5-1, rns2-2 atg9-4, and rns2-2 atg5-1 mutants, suggesting a parallel role for autophagy and RNS2 in RNA turnover. rRNA accumulates in the vacuole in rns2-2 mutants. Vacuolar accumulation of rRNA was blocked by disrupting autophagy via an rns2-2 atg5-1 double mutant but not by an rns2-2 atg9-4 double mutant, indicating that ATG5 and ATG9 function differently in this process. Our results suggest that autophagy and RNS2 are both involved in homeostatic degradation of rRNA in the vacuole.