The Arabidopsis Protein CGL20 Is Required for Plastid 50S Ribosome Biogenesis1[OPEN]
The Arabidopsis Protein CGL20 Is Required for Plastid 50S Ribosome Biogenesis1[OPEN]
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DOI：
10.1104/pp.19.01502
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发表时间：
2020-03-01
期刊：
影响因子：
7.4
通讯作者：
Ruehle, Thilo
中科院分区：
文献类型：
--
作者：
Reiter, Bennet;Vamvaka, Evgenia;Ruehle, Thilo
一种绿色谱系特异性蛋白参与质体核糖体生物合成的后期阶段，它通过加工和修饰核糖体RNA（rRNA）或参与核糖体组装的辅助因子促进质体核糖体的生物合成。与它们的细菌和线粒体对应物相比，质体核糖体的生物发生还不太清楚，迄今为止几乎没有描述过辅助因子。在这项研究中，我们报告的功能特性的保护只在绿色的线20（CGL 20）在拟南芥（拟南芥; AtCGL 20），这是一个Pro丰富的，类似于10 kD的蛋白质，是针对线粒体和叶绿体。在拟南芥中，CGL 20由具有高序列相似性的片段重复基因（AtCGL 20 A和AtCGL 20 B）编码。这些基因在atcgl 20 ab突变体中的失活导致可见的存活表型和低温下的生长停滞。atcgl 20 ab突变体的叶绿体蛋白质组、色素组成和光合性能受到显著影响。AtCGL 20的损失损害质体翻译，扰乱形成一个隐藏的23 S rRNA的断裂，并导致异常积累的50 S核糖体亚基的叶绿体基质提取物的高分子质量分数。此外，AtCGL 20 A-eGFP融合蛋白与50 S核糖体亚基在Suc密度梯度中共迁移，即使在RNA酶处理基质提取物后。因此，我们建议，AtCGL 20参与质体中的50 S核糖体亚基的生物发生的后期阶段，推测在绿色谱系作为质体核糖体的结构分歧的结果进化的作用。
A green lineage-specific protein is involved in late stages of plastid ribosome biogenesis.Biogenesis of plastid ribosomes is facilitated by auxiliary factors that process and modify ribosomal RNAs (rRNAs) or are involved in ribosome assembly. In comparison with their bacterial and mitochondrial counterparts, the biogenesis of plastid ribosomes is less well understood, and few auxiliary factors have been described so far. In this study, we report the functional characterization of CONSERVED ONLY IN THE GREEN LINEAGE20 (CGL20) in Arabidopsis (Arabidopsis thaliana; AtCGL20), which is a Pro-rich, similar to 10-kD protein that is targeted to mitochondria and chloroplasts. In Arabidopsis, CGL20 is encoded by segmentally duplicated genes of high sequence similarity (AtCGL20A and AtCGL20B). Inactivation of these genes in the atcgl20ab mutant led to a visible virescent phenotype and growth arrest at low temperature. The chloroplast proteome, pigment composition, and photosynthetic performance were significantly affected in atcgl20ab mutants. Loss of AtCGL20 impaired plastid translation, perturbing the formation of a hidden break in the 23S rRNA and causing abnormal accumulation of 50S ribosomal subunits in the high-molecular-mass fraction of chloroplast stromal extracts. Moreover, AtCGL20A-eGFP fusion proteins comigrated with 50S ribosomal subunits in Suc density gradients, even after RNase treatment of stromal extracts. Therefore, we propose that AtCGL20 participates in the late stages of the biogenesis of 50S ribosomal subunits in plastids, a role that presumably evolved in the green lineage as a consequence of structural divergence of plastid ribosomes.