Three Brick genes have distinct functions in a common pathway promoting polarized cell division and cell morphogenesis in the maize leaf epidermis
Three Brick genes have distinct functions in a common pathway promoting polarized cell division and cell morphogenesis in the maize leaf epidermis
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DOI：
10.1242/dev.00290
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发表时间：
2003-02-01
期刊：
影响因子：
4.6
通讯作者：
Smith, LG
中科院分区：
文献类型：
--
作者：
Frank, MJ;Cartwright, HN;Smith, LG
我们已经采取了遗传学的方法来研究细胞骨架依赖的机制，控制细胞形态发生在玉米叶表皮。在此之前，我们发现Brick1 （Brk1）基因是表皮细胞叶的形成以及气孔附属母细胞的正确极化分裂所必需的，并编码一个在植物和动物中高度保守的8kda蛋白。在这里，我们发现另外两个Brick基因Brk2和Brk3参与表皮细胞形态发生和分裂的相同方面。正如之前对Brk1所示，对细胞骨架的分析表明，Brk2和Brk3是野生型细胞中与叶状生长相关的局部f -肌动蛋白富集形成所必需的。brk1分析；brk2 brk1;Brk3和brk2；Brk3双突变体显示其表型与BRK单突变体相同。镶嵌分析表明，Brk1在短距离内非细胞自主作用。相比之下，Brk2和Brk3以细胞自主的方式促进路面细胞裂片的形成，但Brk3和Brk2以非细胞自主的方式促进极化附属母细胞分裂。总之，这些观察结果表明，所有三个Brk基因在一个共同的途径中起作用，其中每个Brk基因具有不同的功能。最近的研究表明，BRK1 （HSPC300）的哺乳动物同源物在激活arp2 /3依赖性肌动蛋白聚合中的作用暗示了Brk途径在植物细胞中局部调节肌动蛋白聚合。
We have taken a genetic approach to investigating cytoskeleton-dependent mechanisms governing cell morphogenesis in the maize leaf epidermis. Previously, we showed that the Brick1 (Brk1) gene is required for the formation of epidermal cell lobes as well as for properly polarized divisions of stomatal subsidiary mother cells, and encodes an 8 kDa protein highly conserved in plants and animals. Here, we show that two additional Brick genes, Brk2 and Brk3, are involved in the same aspects of epidermal cell morphogenesis and division. As shown previously for Brk1, analysis of the cytoskeleton shows that Brk2 and Brk3 are required for the formation of local F-actin enrichments associated with lobe outgrowth in wildtype cells. Analysis of brk1;brk2, brk1;brk3 and brk2;brk3 double mutants shows that their phenotypes are the same as those of brk single mutants. Mosaic analysis shows that Brk1 acts non cell-autonomously over a short distance. By contrast, Brk2 and Brk3 act cell-autonomously to promote pavement cell lobe formation, but Brk3 acts non cell-autonomously, and Brk2 partially non cell-autonomously, to promote polarized subsidiary mother cell divisions. Together, these observations indicate that all three Brk genes act in a common pathway in which each Brk gene has a distinct function. Recent work demonstrating a function for the mammalian homolog of BRK1 (HSPC300) in activation of Arp2/3-dependent actin polymerization implicates the Brk pathway in local regulation of actin polymerization in plant cells.