Balance between Cytosolic and Chloroplast Translation Affects Leaf Variegation
Balance between Cytosolic and Chloroplast Translation Affects Leaf Variegation
复制标题
细胞质和叶绿体翻译之间的平衡影响叶子杂色。
DOI：
10.1104/pp.17.00673
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发表时间：
2018-01-01
期刊：
影响因子：
7.4
通讯作者：
Yu, Fei
中科院分区：
文献类型：
--
作者：
Wang, Ruijuan;Zhao, Jun;Yu, Fei
功能叶绿体的发育依赖于细胞核和叶绿体基因组表达的精细协调。本文以拟南芥（Arabidopsis thaliana）黄斑（var2）叶斑突变体为工具，对叶绿体发育的调控进行了研究。在这项工作中，我们筛选了var2基因增强修饰子，称为杂交增强子（evr）突变体，并报道了第一个evr位点EVR1的特征。我们发现EVR1编码细胞质80S核糖体40S小亚基蛋白RPS21B， EVR1的缺失导致var2叶片杂色增强。我们进一步证明，来自EVR1及其近亲同源基因EVR1L1的S21活性对拟南芥至关重要，它们在调节叶片发育和var2叶片杂色中起冗余作用。此外，通过使用其他细胞质核糖体蛋白突变体，我们发现尽管细胞质核糖体蛋白突变都不同程度地增强了var2叶片斑纹，但在调节var2介导的叶绿体发育方面，40S亚基似乎比60S亚基具有更深远的作用。对叶绿体翻译缺陷的var2抑制基因的综合遗传分析表明，细胞质核糖体蛋白突变体对var2叶片杂色的增强依赖于叶绿体翻译。基于我们的数据，我们提出了一个包含抑制和增强var2叶片杂色的模型，并假设var2 /AtFtsH2可能密切参与叶绿体生物发生过程中细胞质和叶绿体翻译程序的平衡。
The development of functional chloroplasts relies on the fine coordination of expressions of both nuclear and chloroplast genomes. We have been using the Arabidopsis (Arabidopsis thaliana) yellow variegated (var2) leaf variegation mutant as a tool to dissect the regulation of chloroplast development. In this work, we screened for var2 genetic enhancer modifiers termed enhancer of variegation (evr) mutants and report the characterization of the first EVR locus, EVR1. We showed that EVR1 encodes the cytosolic 80S ribosome 40S small subunit protein RPS21B and the loss of EVR1 causes the enhancement of var2 leaf variegation. We further demonstrated that combined S21 activities from EVR1 and its close homolog, EVR1L1, are essential for Arabidopsis, and they act redundantly in regulating leaf development and var2 leaf variegation. Moreover, using additional cytosolic ribosomal protein mutants, we showed that although mutations in cytosolic ribosomal proteins all enhance var2 leaf variegation to varying degrees, the 40S subunit appears to have a more profound role over the 60S subunit in regulating VAR2-mediated chloroplast development. Comprehensive genetic analyses with var2 suppressors that are defective in chloroplast translation established that the enhancement of var2 leaf variegation by cytosolic ribosomal protein mutants is dependent on chloroplast translation. Based on our data, we propose a model that incorporates the suppression and enhancement of var2 leaf variegation, and hypothesize that VAR2/AtFtsH2 may be intimately involved in the balancing of cytosolic and chloroplast translation programs during chloroplast biogenesis.