The Arabidopsis gene YS1 encoding a DYW protein is required for editing of rpoB transcripts and the rapid development of chloroplasts during early growth.
The Arabidopsis gene YS1 encoding a DYW protein is required for editing of rpoB transcripts and the rapid development of chloroplasts during early growth.
复制标题
DOI：
10.1111/j.1365-313x.2008.03766.x
复制
发表时间：
2009-04
期刊：
影响因子：
--
通讯作者：
Wenbin Zhou;Yuxiang Cheng;Aaron Yap;A. Chateigner-Boutin;E. Delannoy;K. Hammani;I. Small;Jirong Huang-Ji
中科院分区：
文献类型：
--
作者：
Wenbin Zhou;Yuxiang Cheng;Aaron Yap;A. Chateigner-Boutin;E. Delannoy;K. Hammani;I. Small;Jirong Huang-Ji
翠绿是一种叶片变绿比平时慢的表型，在健康叶绿体发育之前，被认为在保护免受光氧化损伤方面发挥作用。对绿化的分子机制的阐明将有助于了解叶绿体的发育是如何被控制的。在本研究中，我们发现敲除拟南芥黄苗1 （Yellow幼苗1，YS1）等位基因导致翠绿表型，在发芽后3周消失。ys1突变导致8日龄幼苗光合能力和光合色素复合物明显降低，类囊体膜超微结构受到干扰。然而，在黑暗中处理5天的ys1幼苗子叶在光照下几乎与野生型一样快地变绿，这表明ys1的发育缺陷仅限于发芽后的前几天。对所有已知的质体RNA编辑和剪接事件的检查表明，编码质体编码RNA聚合酶(PEP) β亚基的rpoB转录本中25992位点的编辑绝对需要YS1。YS1是一种核编码的叶绿体定位的五肽重复蛋白，与先前描述的编辑因子不同，它具有c端DYW基序。PEP活性缺陷与在ys1幼苗中观察到的质体转录模式变化一致。我们得出结论，从未经编辑的转录本翻译的含有RpoB的PEP的活性不足以支持叶绿体的快速分化。
Virescence, a phenotype in which leaves green more slowly than usual, is recognized to play a role in protection from photo-oxidative damage before healthy chloroplasts are developed. The elucidation of the molecular mechanisms underlying virescence will provide insights into how the development of chloroplasts is controlled. In this study, we find that knockout alleles of Yellow Seedlings 1 (YS1) in Arabidopsis lead to a virescent phenotype, which disappears by 3 weeks after germination. The ys1 mutation resulted in marked decreases in photosynthetic capacity and photosynthetic pigment complexes, and disturbed ultrastructure of thylakoid membranes in 8-day-old seedlings. However, cotyledons of ys1 seedlings pre-treated in the dark for 5 days turn green almost as fast as the wild type in light, revealing that the developmental defects in ys1 are limited to the first few days after germination. Inspection of all known plastid RNA editing and splicing events revealed that YS1 is absolutely required for editing of site 25992 in rpoB transcripts encoding the beta subunit of the plastid-encoded RNA polymerase (PEP). YS1 is a nuclear-encoded chloroplast-localized pentatricopeptide repeat protein differing from previously described editing factors in that it has a C-terminal DYW motif. A defect in PEP activity is consistent with the changes in plastid transcript patterns observed in ys1 seedlings. We conclude that the activity of PEP containing RpoB translated from unedited transcripts is insufficient to support rapid chloroplast differentiation.