Center for Anatomy & Cell Biology, Medical University of Vienna, Vienna A-1090, Austria.
UMR7156 - Molecular Genetics, Genomics, Microbiology, University of Strasbourg, CNRS, Strasbourg F-67000, France.
Nucleic Acids Res. 2020 Sep 25;48(17):9762-9786. doi: 10.1093/nar/gkaa148.
Ribosome biogenesis requires numerous trans-acting factors, some of which are deeply conserved. In Bacteria, the endoribonuclease YbeY is believed to be involved in 16S rRNA 3'-end processing and its loss was associated with ribosomal abnormalities. In Eukarya, YBEY appears to generally localize to mitochondria (or chloroplasts). Here we show that the deletion of human YBEY results in a severe respiratory deficiency and morphologically abnormal mitochondria as an apparent consequence of impaired mitochondrial translation. Reduced stability of 12S rRNA and the deficiency of several proteins of the small ribosomal subunit in YBEY knockout cells pointed towards a defect in mitochondrial ribosome biogenesis. The specific interaction of mitoribosomal protein uS11m with YBEY suggests that the latter helps to properly incorporate uS11m into the nascent small subunit in its late assembly stage. This scenario shows similarities with final stages of cytosolic ribosome biogenesis, and may represent a late checkpoint before the mitoribosome engages in translation.
核糖体生物发生需要许多反式作用因子，其中一些因子高度保守。在细菌中，内切核酸酶 YbeY 被认为参与 16S rRNA 3'-端加工，其缺失与核糖体异常有关。在真核生物中，YBEY 似乎普遍定位于线粒体（或叶绿体）。在这里，我们表明人类 YBEY 的缺失导致严重的呼吸缺陷和形态异常的线粒体，这显然是由于线粒体翻译受损的结果。YBEY 敲除细胞中 12S rRNA 的稳定性降低和小核糖体亚基的几种蛋白缺乏表明线粒体核糖体生物发生存在缺陷。线粒体核糖体蛋白 uS11m 与 YBEY 的特异性相互作用表明，后者有助于在其晚期组装阶段将 uS11m 正确地掺入新生小亚基中。这种情况与胞质核糖体生物发生的最后阶段相似，并且可能代表线粒体核糖体参与翻译之前的晚期检查点。
