SUMO E3 Ligase HIGH PLOIDY2 Regulates Endocycle Onset and Meristem Maintenance in Arabidopsis
SUMO E3 Ligase HIGH PLOIDY2 Regulates Endocycle Onset and Meristem Maintenance in Arabidopsis
复制标题
DOI：
10.1105/tpc.109.068072
复制
发表时间：
2009-08-01
期刊：
影响因子：
11.6
通讯作者：
Sugimoto, Keiko
中科院分区：
文献类型：
--
作者：
Ishida, Takashi;Fujiwara, Sumire;Sugimoto, Keiko
核内复制涉及染色体DNA的加倍而没有相应的细胞分裂。在植物中，许多细胞类型从有丝分裂周期过渡到核内复制周期或内循环，并且这种过渡通常与细胞扩增和分化的起始相结合。虽然已经确定了一些细胞周期调控因子参与内循环的启动，但在很大程度上仍然不清楚这种转变是如何在整个器官水平上进行发育调控的。在这里，我们报告说，核定位SUMO E3连接酶，高倍性2（HPY 2），作为一个阻遏物的内循环开始在拟南芥分生组织。HPY 2的缺失导致从有丝分裂周期到内周期的过早转变，导致具有缺陷分生组织的严重侏儒症。HPY 2具有MMS 21型SUMO E3连接酶的SP-RING结构域特征，并且我们表明该结构域内的保守残基是HPY 2的体内和体外功能所需的。HPY 2主要在根分生组织的增殖细胞中表达，并且其在分生组织图案化转录因子PLETHORA 1（PLT 1）和PLT 2的下游起作用。这些结果表明，HPY 2介导的类小泛素化调节细胞周期进程和分生组织发育的PLT依赖性信号通路。
Endoreduplication involves a doubling of chromosomal DNA without corresponding cell division. In plants, many cell types transit from the mitotic cycle to the endoreduplication cycle or endocycle, and this transition is often coupled with the initiation of cell expansion and differentiation. Although a number of cell cycle regulators implicated in endocycle onset have been identified, it is still largely unknown how this transition is developmentally regulated at the whole organ level. Here, we report that a nuclear-localized SUMO E3 ligase, HIGH PLOIDY2 (HPY2), functions as a repressor of endocycle onset in Arabidopsis thaliana meristems. Loss of HPY2 results in a premature transition from the mitotic cycle to the endocycle, leading to severe dwarfism with defective meristems. HPY2 possesses an SP-RING domain characteristic of MMS21-type SUMO E3 ligases, and we show that the conserved residues within this domain are required for the in vivo and in vitro function of HPY2. HPY2 is predominantly expressed in proliferating cells of root meristems and it functions downstream of meristem patterning transcription factors PLETHORA1 (PLT1) and PLT2. These results establish that HPY2-mediated sumoylation modulates the cell cycle progression and meristem development in the PLT-dependent signaling pathway.