Control of endoreduplication of trichome by RPT2a, a subunit of the 19S proteasome in Arabidopsis
Control of endoreduplication of trichome by RPT2a, a subunit of the 19S proteasome in Arabidopsis
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DOI：
10.1007/s10265-010-0321-x
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发表时间：
2010-03
影响因子：
2.8
通讯作者：
Kaori Sako;Y. Maki;Kumiko K. Imai;T. Aoyama;Derek B. Goto;J. Yamaguchi
中科院分区：
文献类型：
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作者：
Kaori Sako;Y. Maki;Kumiko K. Imai;T. Aoyama;Derek B. Goto;J. Yamaguchi
泛素/26 S蛋白酶体途径在短寿命调节蛋白的降解中起着重要作用，以控制许多细胞事件。拟南芥基因敲除突变体2a，其中包含一个缺陷的AtRPT 2a亚基的26 S蛋白酶体调节颗粒，表现出扩大的叶片所造成的细胞大小增加，与倍性增加所造成的延长核内复制。为了阐明RPT 2a在细胞核内复制调控中的作用，我们对毛状体的发育进行了详细的遗传学研究。RHL 1和GL 3编码的蛋白在毛状体的内循环进程中具有正向调节作用。Therhll突变体在8 ℃下停滞，并且具有仅具有单个分支的毛状体。Therpt 2a突变体的表型与singlerhl 1突变体的表型相似，而Therpt 2a突变体的表型与singlerhl 1突变体的表型相似。另一方面，therpt 2突变抑制gl 3表型（停滞在16 C，两个毛状体分支），并且doublerpt 2a gl 3突变体的毛状体类似于野生型（WT）植物的那些。总之，这些数据表明，RPT 2a的功能，负调控内循环进程后完成的第三个核内复制步骤RHL 1（8 C-16 C）介导的。
The ubiquitin/26S proteasome pathway plays a central role in the degradation of short-lived regulatory proteins to control many cellular events. The Arabidopsis knockout mutantrpt2a, which contains a defect in the AtRPT2a subunit of the 26S proteasome regulatory particle, showed enlarged leaves caused by increased cell size that correlated with increased ploidy caused by extended endoreduplication. To clarify the role of RPT2a in endoreduplication control, trichome development was genetically examined in further detail.RHL1andGL3encode proteins that have a role in the positive regulation of endocycle progression in trichomes. Therhl1mutants are stalled at 8C and have trichomes with only a single branch. Therpt2amutation did not alter therhl1mutant phenotype, and trichomes of doublerpt2a rhl1mutants resembled that of singlerhl1mutants. On the other hand, therpt2amutation suppressed thegl3phenotype (stalled at 16C, two trichome branches), and trichomes of the doublerpt2a gl3mutant resembled those of the wild type (WT) plants. Together, these data suggest that RPT2a functions to negatively regulate endocycle progression following completion of the third endoreduplication step mediated by RHL1 (8C–16C).