Interaction of the pentatricopeptide-repeat protein DELAYED GREENING 1 with sigma factor SIG6 in the regulation of chloroplast gene expression in Arabidopsis cotyledons
Interaction of the pentatricopeptide-repeat protein DELAYED GREENING 1 with sigma factor SIG6 in the regulation of chloroplast gene expression in Arabidopsis cotyledons
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五肽重复蛋白DELAYED GREENING 1与Sigma因子SIG6在拟南芥子叶叶绿体基因表达调控中的相互作用
DOI：
10.1111/j.1365-313x.2010.04304.x
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发表时间：
2010-10-01
期刊：
影响因子：
7.2
通讯作者：
Zhang, Lixin
中科院分区：
文献类型：
--
作者：
Chi, Wei;Mao, Juan;Zhang, Lixin
五肽重复（PPR）蛋白延迟绿化1 （DG1）参与拟南芥早期叶绿体发育和叶绿体基因表达的调控。为了深入了解DG1的作用模式，我们使用酵母双杂交筛选方法并鉴定了一个伙伴SIG6，这是一个叶绿体sigma因子，负责子叶中质体编码RNA聚合酶（PEP）依赖的叶绿体基因的转录。进一步分析表明，DG1的c端区域和SIG6的n端区域负责这种相互作用。截断的c末端DG1在野生型拟南芥中高水平表达导致显性阴性表型。sig6dg1双突变体表现出更严重的褪绿表型，与单突变体相比，pep依赖的叶绿体基因转录物水平大大降低。SIG6的过表达修复了dg1子叶的叶绿素缺失，但没有修复幼叶的叶绿素缺失。此外，在dg1突变背景下，SIG6的增加促进了pep依赖性叶绿体基因转录物的积累。这些结果表明，DG1和SIG6的相互作用在调节拟南芥子叶pep依赖的叶绿体基因转录中具有重要的功能意义。
P>The pentatricopeptide-repeat (PPR) protein DELAYED GREENING 1 (DG1) has been shown to be involved in the regulation of early chloroplast development and chloroplast gene expression in Arabidopsis. To gain insight into the mode of DG1 action, we used a yeast two-hybrid screening approach and identified a partner, SIG6, which is a chloroplast sigma factor responsible for the transcription of plastid-encoded RNA polymerase (PEP)-dependent chloroplast genes in cotyledons. Further analysis showed that the C-terminal region of DG1 and the N-terminal region of SIG6 are responsible for such interactions. High-level expression of a truncated C-terminal DG1 in wild-type Arabidopsis caused a dominant-negative phenotype. The sig6 dg1 double mutant displayed a more severe chlorotic phenotype, and the PEP-dependent chloroplast gene transcripts were greatly reduced compared with transcript levels in the single mutants. Overexpression of SIG6 rescued the chlorophyll deficiency in dg1 cotyledons but not in young leaves. In addition, increased SIG6 promoted PEP-dependent chloroplast gene transcript accumulation in the dg1 mutant background. These results suggest that the interaction of DG1 and SIG6 is functionally significant in the regulation of PEP-dependent chloroplast gene transcription in Arabidopsis cotyledons.