The nuclear-encoded factor HCF173 is involved in the initiation of translation of the psbA mRNA in Arabidopsis thaliana
The nuclear-encoded factor HCF173 is involved in the initiation of translation of the psbA mRNA in Arabidopsis thaliana
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DOI：
10.1105/tpc.106.042895
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发表时间：
2007-04-01
期刊：
影响因子：
11.6
通讯作者：
Westhoff, Peter
中科院分区：
文献类型：
--
作者：
Schult, Kerstin;Meierhoff, Karin;Westhoff, Peter
为了深入了解光系统II （PSII）的生物发生机制，并确定这一过程所需的辅助因子，我们对拟南芥（Arabidopsis thaliana）突变体hcf173进行了表征。该突变体表现出高叶绿素荧光表型（hcf），并严重影响PSII亚基的积累。体内标记实验显示反应中心蛋白D1的合成急剧减少。多体关联实验表明，这主要是由于相应的psbA mRNA的翻译起始减少引起的。mRNA稳态水平比较表明，hcf173中psbA mRNA显著减少。此外，psbA mRNA半衰期的测定显示RNA稳定性受损。通过定位克隆鉴定HCF173基因，并通过hcf表型的互补证实其同源性。HCF173编码一种与短链脱氢酶/还原酶超家族有微弱相似性的蛋白质。HCF173蛋白定位于叶绿体，主要与膜系统相关，是高分子量复合物的一部分。HCF173融合蛋白的亲和层析发现psbA mRNA是该复合物的一个组成部分。
To gain insight into the biogenesis of photosystem II (PSII) and to identify auxiliary factors required for this process, we characterized the mutant hcf173 of Arabidopsis thaliana. The mutant shows a high chlorophyll fluorescence phenotype (hcf) and is severely affected in the accumulation of PSII subunits. In vivo labeling experiments revealed a drastically decreased synthesis of the reaction center protein D1. Polysome association experiments suggest that this is primarily caused by reduced translation initiation of the corresponding psbA mRNA. Comparison of mRNA steady state levels indicated that the psbA mRNA is significantly reduced in hcf173. Furthermore, the determination of the psbA mRNA half-life revealed an impaired RNA stability. The HCF173 gene was identified by map-based cloning, and its identity was confirmed by complementation of the hcf phenotype. HCF173 encodes a protein with weak similarities to the superfamily of the short-chain dehydrogenases/ reductases. The protein HCF173 is localized in the chloroplast, where it is mainly associated with the membrane system and is part of a higher molecular weight complex. Affinity chromatography of an HCF173 fusion protein uncovered the psbA mRNA as a component of this complex.