ATAB2 is a novel factor in the signalling pathway of light-controlled synthesis of photosystem proteins
ATAB2 is a novel factor in the signalling pathway of light-controlled synthesis of photosystem proteins
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DOI：
10.1038/sj.emboj.7601472
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发表时间：
2006-12-13
期刊：
影响因子：
11.4
通讯作者：
Rochaix, Jean-David
中科院分区：
文献类型：
--
作者：
Barneche, Fredy;Winter, Veronika;Rochaix, Jean-David
质体翻译控制在很大程度上取决于光条件，并推测是由细胞核编码的蛋白质作用于细胞器基因表达介导的。然而，参与翻译的光信号传导的分子机制仍然知之甚少。我们研究了拟南芥直向同源物Tab 2的作用，Tab 2是一种核基因，专门用于翻译PsaB光系统I亚基，在单细胞拟南芥衣原体中。ATAB 2的失活强烈影响拟南芥的发育和类囊体膜的生物发生，并导致白化病表型。此外，光系统反应中心亚单位的合成速率降低，其mRNA与多聚核糖体的结合受到影响。ATAB 2是一种富含叶绿体A/U的RNA结合蛋白，推测其作为翻译激活剂与至少两个靶点一起起作用，每个靶点用于每个光系统。在早期幼苗发育过程中，ATAB 2蓝光诱导降低感光突变体，特别是在那些缺乏隐花色素。考虑到其在蛋白质合成及其光受体介导的表达中的作用，ATAB 2代表了植物发育早期光系统蛋白质光控翻译信号传导途径中的一个新因子。
Plastid translational control depends to a large extent on the light conditions, and is presumably mediated by nucleus-encoded proteins acting on organelle gene expression. However, the molecular mechanisms of light signalling involved in translation are still poorly understood. We investigated the role of the Arabidopsis ortholog of Tab2, a nuclear gene specifically required for translation of the PsaB photosystem I subunit in the unicellular alga Chlamydomonas. Inactivation of ATAB2 strongly affects Arabidopsis development and thylakoid membrane biogenesis and leads to an albino phenotype. Moreover the rate of synthesis of the photosystem reaction center sub-units is decreased and the association of their mRNAs with polysomes is affected. ATAB2 is a chloroplast A/U-rich RNA-binding protein that presumably functions as an activator of translation with at least two targets, one for each photosystem. During early seedling development, ATAB2 blue-light induction is lowered in photoreceptor mutants, notably in those lacking cryptochromes. Considering its role in protein synthesis and its photoreceptor-mediated expression, ATAB2 represents a novel factor in the signalling pathway of light-controlled translation of photosystem proteins during early plant development.