Auxin modulates the transition from the mitotic cycle to the endocycle in Arabidopsis
Auxin modulates the transition from the mitotic cycle to the endocycle in Arabidopsis
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DOI：
10.1242/dev.035840
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发表时间：
2010-01-01
期刊：
影响因子：
4.6
通讯作者：
Sugimoto, Keiko
中科院分区：
文献类型：
--
作者：
Ishida, Takashi;Adachi, Sumiko;Sugimoto, Keiko
通过核内复制扩增基因组DNA通常标志着动物和植物中细胞分化的起始。从有丝分裂周期到内周期的转变应该是发育程序化的，但是这个过程是如何被调节的在很大程度上仍然未知。我们表明，植物生长调节剂生长素调制开关从有丝分裂周期的内循环在拟南芥中，高水平的TIR 1-AUX/IAA-ARF依赖生长素信号需要抑制内循环，从而维持细胞在有丝分裂周期。相比之下，较低水平的TIR 1-AUX/IAA-ARF依赖的生长素信号触发退出有丝分裂周期和进入内循环。我们的数据进一步表明，这种生长素介导的有丝分裂到内循环开关的调制与拟南芥根分生组织中从细胞增殖到细胞分化的发育过渡紧密相关。由生长素拮抗剂PEO-IAA的生长素信号的瞬时减少迅速下调几个核心细胞周期基因的表达，我们表明，过表达的基因之一，细胞周期蛋白A2;3（CYCA 2;3），部分抑制由PEO-IAA诱导的细胞分化的早期启动。两者合计，这些结果表明，生长素介导的有丝分裂到内循环的过渡可能是平衡细胞增殖和细胞分化在拟南芥根分生组织的发育计划的一部分。
Amplification of genomic DNA by endoreduplication often marks the initiation of cell differentiation in animals and plants. The transition from mitotic cycles to endocycles should be developmentally programmed but how this process is regulated remains largely unknown. We show that the plant growth regulator auxin modulates the switch from mitotic cycles to endocycles in Arabidopsis; high levels of TIR1-AUX/IAA-ARF-dependent auxin signalling are required to repress endocycles, thus maintaining cells in mitotic cycles. By contrast, lower levels of TIR1-AUX/IAA-ARF-dependent auxin signalling trigger an exit from mitotic cycles and an entry into endocycles. Our data further demonstrate that this auxin-mediated modulation of the mitotic-to-endocycle switch is tightly coupled with the developmental transition from cell proliferation to cell differentiation in the Arabidopsis root meristem. The transient reduction of auxin signalling by an auxin antagonist PEO-IAA rapidly downregulates the expression of several core cell cycle genes, and we show that overexpressing one of the genes, CYCLIN A2;3 (CYCA2;3), partially suppresses an early initiation of cell differentiation induced by PEO-IAA. Taken together, these results suggest that auxin-mediated mitotic-to-endocycle transition might be part of the developmental programmes that balance cell proliferation and cell differentiation in the Arabidopsis root meristem.