The putative Arabidopsis Arp2/3 complex controls leaf cell morphogenesis
The putative Arabidopsis Arp2/3 complex controls leaf cell morphogenesis
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DOI：
10.1104/pp.103.028563
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发表时间：
2003-08-01
期刊：
影响因子：
7.4
通讯作者：
Lord, EM
中科院分区：
文献类型：
--
作者：
Li, SD;Blanchoin, L;Lord, EM
进化上保守的Arp2/3复合物已被证明在几种真核生物中激活肌动蛋白成核和分支，但其生物学功能在多细胞生物中尚不清楚，模式植物拟南芥为遗传解剖这种保守的肌动蛋白成核机制的功能提供了许多优势，但该复合物在植物中的存在尚未确定。我们已经确定了拟南芥基因编码所有7个Arp2/3亚基的同源物。利用ARP2、ARP3和ARPC5/pl6的四个纯合T-DNA插入突变体，研究了推测的A-rabidopsis ARP2 /3复合体的功能。在茶叶中，所有四种突变体在形成锯齿状表皮铺装细胞和支状毛状体方面都表现出相同的缺陷。这些功能突变导致弥漫性皮质f-肌动蛋白在颈部区域的错误定位，并抑制路面细胞的叶延伸。突变体的毛状体类似于那些用肌动蛋白解聚药物细胞松弛素D处理过的毛状体，表现出分支发育迟缓，但由于去极化生长而显着扩大了茎，这表明肌动蛋白精细网络的形成存在缺陷。我们的数据表明，假定的拟南芥Arp2/3复合体通过其在细胞极性建立和极性细胞扩增中的作用来控制细胞形态发生。此外，我们的数据表明，假设的Arp2/3复合物在调节皮质f -肌动蛋白的空间分布方面具有新的功能，并提供证据表明，假设的Arp2/3复合物可能激活特定细胞类型中某些类型肌动蛋白丝的聚合。
The evolutionarily conserved Arp2/3 complex has been shown to activate actin nucleation and branching in several eukaryotes, but its biological functions are not well understood in multicellular organisms, The model plant Arabidopsis provides many advantages for genetic dissection of the function of this conserved actin-nudeating machinery yet the Ar existence of this complex in plants has not been determined. We have identified abidopsis genes encoding homologs of all of the seven Arp2/3 subunits. The function of the putative A-rabidopsis Arp2/3 complex has been studied using four homozygous T-DNA insertion mutants for ARP2, ARP3, and ARPC5/pl6. All four mutants display identical defects in the development of jigsaw-shaped epidermal pavement cells and branched trichomes, in the teaf. These toss-of-function mutations cause mislocalization of diffuse cortical F-actin to the neck region and inhibit lobe extension in pavement cells. The mutant trichomes resemble those treated with the actin-depolymerizing drug cytochalasin D, exhibiting stunted branches but dramatically enlarged stalks due to depolarized growth suggesting defects in the formation of a fine actin network. Our data demonstrate that the putative Arabidopsis Arp2/3 complex controls cell morphogenesis through its roles in cell polarity establishment and polar cell expansion. Furthermore, our data suggest a novel function for the putative Arp2/3 complex in the modulation of the spatial distribution of cortical F-actin and provide evidence that the putative Arp2/3 complex may activate the polymerization of some types of actin filaments in specific cell types.