AKRP and EMB506 are two ankyrin repeat proteins essential for plastid differentiation and plant development in Arabidopsis
AKRP and EMB506 are two ankyrin repeat proteins essential for plastid differentiation and plant development in Arabidopsis
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DOI：
10.1111/j.1365-313x.2006.02922.x
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发表时间：
2006-12-01
期刊：
影响因子：
7.2
通讯作者：
Devic, M.
中科院分区：
文献类型：
--
作者：
Garcion, C.;Guilleminot, J.;Devic, M.
EMB506是一种胚胎发育所必需的叶绿体蛋白，其功能尚不清楚。为了深入了解EMB506的作用，进行了双杂交交互屏幕。在未成熟角果的cDNA文库中发现了一个单一的相互作用伙伴AKRP。AKR基因(Zhang等人，1992，植物细胞4,1575-1588)编码一种含有5个Ankyrin重复序列的蛋白质，与EMB506非常相似。蛋白质截断系列表明，这两种蛋白质通过它们的锚定蛋白结构域相互作用。利用反向遗传学，我们发现AKR功能的丧失导致胚胎缺陷(Emb)表型与emb506表型无法区分。AKRP信号肽与绿色荧光蛋白融合后的瞬时表达证实了AKRP在叶绿体中的定位。利用ABI3启动子以种子特异的方式表达AKR，以分析AKR/AKR幼苗中AKR功能丧失的胚后效应。获得了纯合、可育和存活的AKR/AKR植株。这些植物在叶绿体和叶片细胞组织中表现出轻微到严重的缺陷。我们认为，EMB506和AKRP参与了植物生活史中与细胞分化、形态发生和器官发生密切相关的重要调控事件。
EMB506 is a chloroplast protein essential for embryo development, the function of which is unknown. A two-hybrid interaction screen was performed to provide insight into the role of EMB506. A single interacting partner, AKRP, was identified among a cDNA library from immature siliques. The AKR gene (Zhang et al., 1992, Plant Cell 4, 1575-1588) encodes a protein containing five ankyrin repeats, very similar to EMB506. Protein truncation series demonstrated that both proteins interact through their ankyrin domains. Using reverse genetics, we showed that loss of akr function resulted in an embryo-defective (emb) phenotype indistinguishable from the emb506 phenotype. Transient expression of the signal peptide of AKRP fused to green fluorescent protein demonstrated the chloroplast localization of AKRP. The ABI3 promoter was used to express AKR in a seed-specific manner in order to analyse the post-embryonic effect of AKR loss of function in akr/akr seedlings. Homozygous fertile and viable akr/akr plants were obtained. These plants exhibited mild to severe defects in chloroplast and leaf cellular organization. We conclude that EMB506 and AKRP are involved in crucial and tightly controlled events in plastid differentiation linked to cell differentiation, morphogenesis and organogenesis during the plant life cycle.