Chloroplast division in higher plants requires members of two functionally divergent gene families with homology to bacterial ftsZ
Chloroplast division in higher plants requires members of two functionally divergent gene families with homology to bacterial ftsZ
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DOI：
10.1105/tpc.10.12.1991
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发表时间：
1998-12-01
期刊：
影响因子：
11.6
通讯作者：
Lee, WY
中科院分区：
文献类型：
--
作者：
Osteryoung, KW;Stokes, KD;Lee, WY
质体的分裂对于光合作用真核生物的生存至关重要，但与此过程相关的机制仍然知之甚少。我们之前从拟南芥中鉴定出一个核基因，编码细菌细胞分裂蛋白 FtsZ 的叶绿体定位同源物，FtsZ 是原核细胞分裂装置的重要细胞骨架成分。在这里，我们报告了从拟南芥中鉴定出第二种核编码的 FtsZ 型蛋白，该蛋白不包含叶绿体靶向序列或其他明显的分选信号，并且不会导入分离的叶绿体中，这强烈表明它位于细胞质中。我们进一步证明，使用反义技术抑制转基因植物中拟南芥 FtsZ 基因（AtFfsZ1-1 或 AtFtsZ2-1）的表达，可将成熟叶细胞中叶绿体的数量从 100 个减少到 1 个，表明这两个基因对于高等植物叶绿体的分裂至关重要，但每个基因在此过程中都发挥着独特的作用。对目前可用的植物 FtsZ 序列的分析进一步表明，编码差异定位产物的两个功能不同的 FtsZ 基因家族参与叶绿体分裂。我们的结果提供了证据，表明 FtsZ 的叶绿体和细胞质形式都参与高等植物的叶绿体分裂，这意味着叶绿体和原核生物之间在 FtsZ 蛋白在分裂过程中所发挥的作用方面存在重要差异。
The division of plastids is critical for viability in photosynthetic eukaryotes, but the mechanisms associated with this process are still poorly understood. We previously identified a nuclear gene from Arabidopsis encoding a chloroplast-localized homolog of the bacterial cell division protein FtsZ, an essential cytoskeletal component of the prokaryotic cell division apparatus. Here, we report the identification of a second nuclear-encoded FtsZ-type protein from Arabidopsis that does not contain a chloroplast targeting sequence or other obvious sorting signals and is not imported into isolated chloroplasts, which strongly suggests that it is localized in the cytosol. We further demonstrate using antisense technology that inhibiting expression of either Arabidopsis FtsZ gene (AtFfsZ1-1 or AtFtsZ2-1) in transgenic plants reduces the number of chloroplasts in mature leaf cells from 100 to one, indicating that both genes are essential for division of higher plant chloroplasts but that each plays a distinct role in the process. Analysis of currently available plant FtsZ sequences further suggests that two functionally divergent FtsZ gene families encoding differentially localized products participate in chloroplast division. Our results provide evidence that both chloroplastic and cytosolic forms of FtsZ are involved in chloroplast division in higher plants and imply that important differences exist between chloroplasts and prokaryotes with regard to the roles played by FtsZ proteins in the division process.