Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.
Development. 2009 Dec;136(24):4123-32. doi: 10.1242/dev.039099. Epub 2009 Nov 11.
Planar cell polarity is an important characteristic of many epithelia. In the Drosophila wing, eye and abdomen, establishment of planar cell polarity requires the core planar cell polarity genes and two cadherins, Fat and Dachsous. Drosophila Fat2 is a cadherin related to Fat; however, its role during planar cell polarity has not been studied. Here, we have generated mutations in fat2 and show that Fat2 is required for the planar polarity of actin filament orientation at the basal side of ovarian follicle cells. Defects in actin filament orientation correlate with a failure of egg chambers to elongate during oogenesis. Using a functional fosmid-based fat2-GFP transgene, we show that the distribution of Fat2 protein in follicle cells is planar polarized and that Fat2 localizes where basal actin filaments terminate. Mosaic analysis demonstrates that Fat2 acts non-autonomously in follicle cells, indicating that Fat2 is required for the transmission of polarity information. Our results suggest a principal role for Fat-like cadherins during the establishment of planar cell polarity.
平面细胞极性是许多上皮组织的一个重要特征。在果蝇的翅膀、眼睛和腹部中，建立平面细胞极性需要核心平面细胞极性基因和两种钙粘蛋白，Fat 和 Dachsous。果蝇 Fat2 是一种与 Fat 相关的钙粘蛋白；然而，其在平面细胞极性中的作用尚未得到研究。在这里，我们生成了 fat2 的突变，并表明 Fat2 对于卵母细胞滤泡细胞基底侧肌动蛋白丝取向的平面极性是必需的。肌动蛋白丝取向的缺陷与卵母细胞在卵子发生过程中不能伸长有关。使用基于功能的 fosmid 的 fat2-GFP 转基因，我们表明 Fat2 蛋白在滤泡细胞中的分布是平面极化的，并且 Fat2 定位于基底肌动蛋白丝终止的位置。嵌合体分析表明 Fat2 在滤泡细胞中是非自主作用的，表明 Fat2 对于极性信息的传递是必需的。我们的结果表明 Fat 样钙粘蛋白在建立平面细胞极性过程中起主要作用。
