Quality control system that monitors ribosomes damaged by verotoxin

Verotoxin是由肠出血性大肠杆菌产生的。杆菌它靶向宿主核糖体RNA中称为SRL（Sarcin-Ricin Loop）的小结构域。这种毒素的靶位点被精确地确定;然而，这种损伤的后果，包括对核糖体功能和细胞应激反应系统的影响，尚未被广泛探讨。在这项研究中，我们解决了这个问题使用S。酿酒系统作为模型。我们发现，在SRL突变的25 S rRNA是非功能性的，并在体内选择性降解。从5000酵母基因敲除收集突变株，我们确定了几个菌株积累的SRL突变25 S rRNA。有趣的是，参与SRL突变体降解的基因与参与25 S NRD（另一种非功能性25 S rRNA的降解途径）的基因部分重叠。这些结果表明，一个通用的质量控制机制，监测大量的缺陷所造成的一些原因。

Verotoxin is produced by enterohemorrhagic E. coli. It targets a small domain called SRL (Sarcin-Ricin Loop) in the host ribosomal RNA. The target site of this toxin was precisely determined; however, the consequence of this damage, including the effect on the ribosomal function and the cellular stress-response systems, has not been explored extensively. In this research, we tackled this problem using S. cerevisiae system as a model. We revealed that 25S rRNA with a mutation in SRL is nonfunctional and selectively degraded in vivo. From 5000 mutant strains of the yeast knock-out collection, we identified several strains that accumulate the SRL mutant 25S rRNA. Interestingly, the genes involved in the degradation of the SRL mutant are partially overlapped with those involved in 25S NRD (degradation pathway for another type of nonfunctional 25S rRNA). These results suggest a general quality control mechanism that monitors a wealth of defects caused by a number of reasons.