Plant Molecular Biology (Botany), Department Biology I, Ludwig-Maximilians-University Munich, Großhaderner Str. 2, D-82152 Martinsried, Germany.
Plant Molecular Biology (Botany), Department Biology I, Ludwig-Maximilians-University Munich, Großhaderner Str. 2, D-82152 Martinsried, Germany
Mol Plant. 2014 Jul;7(7):1228-47. doi: 10.1093/mp/ssu066. Epub 2014 May 29.
Changes in organellar gene expression (OGE) trigger retrograde signaling. The molecular dissection of OGE-dependent retrograde signaling based on analyses of mutants with altered OGE is complicated by compensatory responses that mask the primary signaling defect and by secondary effects that influence other retrograde signaling pathways. Therefore, to identify the earliest effects of altered OGE on nuclear transcript accumulation, we have induced OGE defects in adult plants by ethanol-dependent repression of PRORS1, which encodes a prolyl-tRNA synthetase located in chloroplasts and mitochondria. After 32h of PRORS1 repression, the translational capacity of chloroplasts was reduced, and this effect subsequently intensified, while basic photosynthetic parameters were still unchanged at 51h. Analysis of changes in whole-genome transcriptomes during exposure to ethanol revealed that induced PRORS1 silencing affects the expression of 1020 genes in all. Some of these encode photosynthesis-related proteins, including several down-regulated light-harvesting chlorophyll a/b binding (LHC) proteins. Interestingly, genes for presumptive endoplasmic reticulum proteins are transiently up-regulated. Furthermore, several NAC-domain-containing proteins are among the transcription factors regulated. Candidate cis-acting elements which may coordinate the transcriptional co-regulation of genes sets include both G-box variants and sequence motifs with no similarity to known plant cis-elements.
细胞器基因表达 (OGE) 的变化会引发逆行信号。基于对 OGE 改变的突变体的分析，对 OGE 依赖性逆行信号的分子剖析受到补偿反应的复杂化，这些补偿反应掩盖了主要的信号缺陷，以及影响其他逆行信号通路的二次效应。因此，为了确定 OGE 改变对核转录物积累的最早影响，我们通过乙醇依赖性抑制 PRORS1 来诱导成年植物中的 OGE 缺陷，PRORS1 编码一种位于叶绿体和线粒体中的脯氨酰-tRNA 合成酶。在 PRORS1 抑制 32 小时后，叶绿体的翻译能力降低，这种效应随后加剧，而在 51 小时时基本光合作用参数仍未改变。在暴露于乙醇过程中对全基因组转录组变化的分析表明，诱导的 PRORS1 沉默会影响所有 1020 个基因的表达。其中一些基因编码与光合作用相关的蛋白质，包括几个下调的光捕获叶绿素 a/b 结合 (LHC) 蛋白。有趣的是，假定内质网蛋白的基因短暂地上调。此外，几个 NAC 结构域包含蛋白是受调控的转录因子之一。可能协调基因集合转录共调控的候选顺式作用元件包括 G 框变体和与已知植物顺式元件没有相似性的序列基序。
