Arabidopsis cotyledon-specific chloroplast biogenesis factor CYO1 is a protein disulfide isomerase
Arabidopsis cotyledon-specific chloroplast biogenesis factor CYO1 is a protein disulfide isomerase
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DOI：
10.1105/tpc.107.051714
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发表时间：
2007-10-01
期刊：
影响因子：
11.6
通讯作者：
Takamiya, Ken-ichiro
中科院分区：
文献类型：
--
作者：
Shimada, Hiroshi;Mochizuki, Mariko;Takamiya, Ken-ichiro
子叶中的叶绿体发育与真叶中的叶绿体发育有许多不同之处，但叶绿体生物发生的子叶特异性程序尚未阐明。拟南芥中的cyo 1突变体具有白化病子叶，但具有正常的绿色真叶。在光照下生长的cyo 1突变体植物中，叶绿体发育异常，但在黑暗中生长的突变体中，叶绿体发育正常。我们通过T-DNA标记分离CYO 1，并通过互补验证突变等位基因负责白化病子叶表型。CYO 1具有与大肠杆菌DnaJ类似的C-4型锌指结构域。CYO 1主要在光照条件下的幼植物中表达，并且CYO 1蛋白定位于叶绿体中的类囊体膜。核光合基因的转录通常不受CYO 1突变的影响，但CYO 1突变体中光合蛋白的水平降低。重组CYO 1可加速模型底物胰岛素中的二硫键还原并使RNase A复性，表明CYO 1具有蛋白质二硫键异构酶活性。这些结果表明，CYO 1具有子叶类囊体生物合成所需的伴侣样活性。
Chloroplast development in cotyledons differs in a number of ways from that in true leaves, but the cotyledon-specific program of chloroplast biogenesis has not been clarified. The cyo1 mutant in Arabidopsis thaliana has albino cotyledons but normal green true leaves. Chloroplasts develop abnormally in cyo1 mutant plants grown in the light, but etioplasts are normal in mutants grown in the dark. We isolated CYO1 by T-DNA tagging and verified that the mutant allele was responsible for the albino cotyledon phenotype by complementation. CYO1 has a C-4-type zinc finger domain similar to that of Escherichia coli DnaJ. CYO1 is expressed mainly in young plants under light conditions, and the CYO1 protein localizes to the thylakoid membrane in chloroplasts. Transcription of nuclear photosynthetic genes is generally unaffected by the CYO1 mutation, but the level of photosynthetic proteins is decreased in CYO1 mutants. Recombinant CYO1 accelerates disulfide bond reduction in the model substrate insulin and renatures RNase A, indicating that CYO1 has protein disulfide isomerase activity. These results suggest that CYO1 has a chaperone-like activity required for thylakoid biogenesis in cotyledons.