REDUCED CHLOROPLAST COVERAGE genes from Arabidopsis thaliana help to establish the size of the chloroplast compartment
REDUCED CHLOROPLAST COVERAGE genes from Arabidopsis thaliana help to establish the size of the chloroplast compartment
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DOI：
10.1073/pnas.1515741113
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发表时间：
2016-02-23
影响因子：
11.1
通讯作者：
Osteryoung, Katherine W.
中科院分区：
文献类型：
--
作者：
Larkin, Robert M.;Stefano, Giovanni;Osteryoung, Katherine W.
真核细胞需要一些机制来确定特定细胞器的细胞体积比例。人们对这些机制知之甚少。从拟南芥质体到核信号突变体的筛选，我们克隆了一个基因的突变等位基因，该基因编码一种功能未知的蛋白质，该蛋白质与其他两个功能未知的拟南芥基因和FRIENDLY同源，该基因以前被证明可以促进拟南芥线粒体的正常分布。与FRIENDLY相反，FRIENDLY的这三个同源物仅在光合生物中发现。基于这些数据，我们提出FRIENDLY扩展成一个小的基因家族，以帮助调节含有线粒体和叶绿体的细胞的能量代谢。事实上，我们发现敲除这些基因会导致许多叶绿体表型，包括叶绿体细胞体积比例减少到野生型的50%。因此，我们将这些基因称为减少的叶绿体覆盖（REC）。在rec1突变体中，叶绿体隔室的大小减少最多。REC1蛋白在细胞质和细胞核中均有表达。REC1被排除在细胞核外时，植物用amitrole，抑制细胞的扩张和叶绿体功能。我们的结论是，REC1是一种质外蛋白，有助于建立叶绿体隔室的大小，来自细胞扩增或叶绿体的信号可以调节REC1。
Eukaryotic cells require mechanisms to establish the proportion of cellular volume devoted to particular organelles. These mechanisms are poorly understood. From a screen for plastid-to-nucleus signaling mutants in Arabidopsis thaliana, we cloned a mutant allele of a gene that encodes a protein of unknown function that is homologous to two other Arabidopsis genes of unknown function and to FRIENDLY, which was previously shown to promote the normal distribution of mitochondria in Arabidopsis. In contrast to FRIENDLY, these three homologs of FRIENDLY are found only in photosynthetic organisms. Based on these data, we proposed that FRIENDLY expanded into a small gene family to help regulate the energy metabolism of cells that contain both mitochondria and chloroplasts. Indeed, we found that knocking out these genes caused a number of chloroplast phenotypes, including a reduction in the proportion of cellular volume devoted to chloroplasts to 50% of wild type. Thus, we refer to these genes as REDUCED CHLOROPLAST COVERAGE (REC). The size of the chloroplast compartment was reduced most in rec1 mutants. The REC1 protein accumulated in the cytosol and the nucleus. REC1 was excluded from the nucleus when plants were treated with amitrole, which inhibits cell expansion and chloroplast function. We conclude that REC1 is an extraplastidic protein that helps to establish the size of the chloroplast compartment, and that signals derived from cell expansion or chloroplasts may regulate REC1.