Venema Dennis R, Zeev-Ben-Mordehai Tzviya, Auld Vanessa J
Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4.
Dev Biol. 2004 Nov 15;275(2):301-14. doi: 10.1016/j.ydbio.2004.07.040.
In Drosophila, wing hairs are aligned in a distally oriented, parallel array. The frizzled pathway determines proximal-distal cell polarity in the wing; however, in frizzled pathway mutants, wing hairs remain parallel. How wing hairs align has not been determined. We have demonstrated a novel role for the septate junction proteins Gliotactin (Gli) and Coracle (Cora) in this process. Prior to prehair extension, Gli and Cora were restricted to basolateral membranes. During pupal prehair development, Gli and Cora transiently formed apical ribbons oriented from the distal wing tip to the proximal hinge. These ribbons were aligned beneath prehair bases and persisted for several hours. During this time, Gli was lost entirely from the basolateral domain. A Gliotactin mutation altered the apical polarization Gli and Cora and induced defects in hair alignment in pupal and adult stages. Genetic and cell biological assays demonstrated that Gli and Cora function to align hairs independently of frizzled. Taken together, our results indicate that Gli and Cora function as the first-identified members of a long-predicted, frizzled-independent parallel alignment mechanism. We propose a model whereby the apical polarization of Gli and Cora functions to stabilize and align prehairs relative to anterior-posterior cell boundaries during pupal wing development.
在果蝇中，翅毛呈向远端定向的平行排列。卷曲蛋白信号通路决定翅中近端到远端的细胞极性；然而，在卷曲蛋白信号通路突变体中，翅毛仍保持平行。翅毛如何排列尚未确定。我们已经证明了分隔连接蛋白胶质肌动蛋白（Gli）和类肌动蛋白（Cora）在此过程中具有新的作用。在毛原细胞延伸之前，Gli和Cora局限于基底外侧膜。在蛹期毛原细胞发育过程中，Gli和Cora短暂地形成从翅尖远端到近端铰链的顶端带。这些带排列在毛原细胞基部下方并持续数小时。在此期间，Gli完全从基底外侧区域消失。胶质肌动蛋白突变改变了Gli和Cora的顶端极化，并在蛹期和成虫期诱导毛排列缺陷。遗传和细胞生物学分析表明，Gli和Cora独立于卷曲蛋白发挥使毛排列的功能。综上所述，我们的结果表明，Gli和Cora作为长期预测的、独立于卷曲蛋白的平行排列机制中首个被鉴定的成员发挥作用。我们提出了一个模型，即Gli和Cora的顶端极化在蛹期翅发育过程中相对于前后细胞边界稳定并排列毛原细胞。
