VAN3 ARF-GAP-mediated vesicle transport is involved in leaf vascular network formation
VAN3 ARF-GAP-mediated vesicle transport is involved in leaf vascular network formation
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DOI：
10.1242/dev.01716
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发表时间：
2005-04-01
期刊：
影响因子：
4.6
通讯作者：
Fukuda, H
中科院分区：
文献类型：
--
作者：
Koizumi, K;Naramoto, S;Fukuda, H
在被子植物的叶片中，维管系统以复杂的网络模式构建，称为脉络。这种脉型的形成作为植物组织模式形成的范例被广泛研究。为了阐明控制静脉模式过程的分子机制，我们先前分离了拟南芥突变体van1至van7，这些突变体表现出不连续的静脉模式。在这里，我们报道了van3突变体与生长素信号传导和极性运输的表型分析，以及van3基因和蛋白质的分子特征。pin1、emb30-7/gn和mp的双突变体分析，以及生长素诱导标记DR5::GUS和生长素运输抑制剂的生理分析表明，VAN3可能参与生长素信号转导，但不参与生长素的极性运输。定位克隆鉴定VAN3基因编码二磷酸腺苷(ADP)-核糖基化因子-鸟苷三磷酸酶（GTPase）激活蛋白（ARF-GAP）。它类似于动物ACAPs，包含四个结构域：BAR （BIN/amphiphysin/RVS）结构域、pleckstrin同源结构域、ARF-GAP结构域和锚蛋白（ANK）重复结构域。重组VAN3蛋白具有gtpase激活活性，对磷脂酰肌醇具有特异性亲和力。该蛋白在酵母双杂交系统中可通过n端BAR结构域自结合。通过双染色对金星标记的VAN3和几种绿色荧光蛋白标记的细胞内标记物进行亚细胞定位分析表明，VAN3位于反式高尔基网络（TGN）的一个亚群中。我们的研究结果表明，该基因的表达受生长素诱导，并受VAN3自身的正向调节，并且一种特定的ACAP类型的ARF-GAP通过tgn介导的囊泡运输系统调节生长素信号传导，在静脉模式形成中起作用。
Within the leaf of an angiosperm, the vascular system is constructed in a complex network pattern called venation. The formation of this vein pattern has been widely studied as a paradigm of tissue pattern formation in plants. To elucidate the molecular mechanism controlling the vein patterning process, we previously isolated Arabidopsis mutants van1 to van7, which show a discontinuous vein pattern. Here we report the phenotypic analysis of the van3 mutant in relation to auxin signaling and polar transport, and the molecular characterization of the VAN3 gene and protein. Double mutant analyses with pin1, emb30-7/gn and mp, and physiological analyses using the auxin-inducible marker DR5::GUS and an auxin transport inhibitor indicated that VAN3 may be involved in auxin signal transduction, but not in polar auxin transport. Positional cloning identified VAN3 as a gene that encodes an adenosine diphosphate (ADP)-ribosylation factor-guanosine triphosphatase (GTPase) activating protein (ARF-GAP). It resembles animal ACAPs and contains four domains: a BAR (BIN/amphiphysin/RVS) domain, a pleckstrin homology (PH) domain, an ARF-GAP domain and an ankyrin (ANK)-repeat domain. Recombinant VAN3 protein showed GTPase-activating activity and a specific affinity for phosphatidylinositols. This protein can self-associate through the N-terminal BAR domain in the yeast two-hybrid system. Subcellular localization analysis by double staining for Venus-tagged VAN3 and several green-fluorescent-protein-tagged intracellular markers indicated that VAN3 is located in a subpopulation of the trans-Golgi network (TGN). Our results indicate that the expression of this gene is induced by auxin and positively regulated by VAN3 itself, and that a specific ACAP type of ARF-GAP functions in vein pattern formation by regulating auxin signaling via a TGN-mediated vesicle transport system.