BIN4, a novel component of the plant DNA topoisomerase VI complex, is required for endoreduplication in Arabidopsis
BIN4, a novel component of the plant DNA topoisomerase VI complex, is required for endoreduplication in Arabidopsis
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DOI：
10.1105/tpc.107.054833
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发表时间：
2007-11-01
期刊：
影响因子：
11.6
通讯作者：
Sugimoto-Shirasua, Keiko
中科院分区：
文献类型：
--
作者：
Breuer, Christian;Stacey, Nicola J.;Sugimoto-Shirasua, Keiko
植物器官如何生长到最终的大小是一个重要但基本上没有答案的问题。在这里，我们描述了一个拟南芥突变体，油菜素类固醇不敏感4（bin 4），其中各种器官的生长显着减少。箱4中的小器官大小主要是由与核内复制增加倍性的缺陷相关的细胞扩增减少引起的。通过秋水仙素诱导的多倍化提高bin 4中的核DNA含量部分地挽救了细胞和器官大小表型，这表明BIN 4是核内复制而不是随后的细胞扩增所直接和特异性需要的。BIN 4编码植物特异性DNA结合蛋白，其充当植物DNA拓扑异构酶VI复合物的组分。在有丝分裂后的细胞中，BIN 4的丢失触发ATM和ATR依赖的DNA损伤反应，并且这种反应与相同细胞类型中细胞周期蛋白B1;1基因的上调相一致，表明DNA损伤反应和内循环控制之间存在功能联系。
How plant organs grow to reach their final size is an important but largely unanswered question. Here, we describe an Arabidopsis thaliana mutant, brassinosteroid-insensitive4 (bin4), in which the growth of various organs is dramatically reduced. Small organ size in bin4 is primarily caused by reduced cell expansion associated with defects in increasing ploidy by endoreduplication. Raising nuclear DNA content in bin4 by colchicine-induced polyploidization partially rescues the cell and organ size phenotype, indicating that BIN4 is directly and specifically required for endoreduplication rather than for subsequent cell expansion. BIN4 encodes a plant-specific, DNA binding protein that acts as a component of the plant DNA topoisomerase VI complex. Loss of BIN4 triggers an ATM- and ATR-dependent DNA damage response in postmitotic cells, and this response coincides with the upregulation of the cyclin B1;1 gene in the same cell types, suggesting a functional link between DNA damage response and endocycle control.