Ma C, Moses K
Department of Biological Sciences, University of Southern California, Los Angeles 90089-1340, USA.
Development. 1995 Aug;121(8):2279-89. doi: 10.1242/dev.121.8.2279.
In the developing Drosophila compound eye, a wave of pattern formation and cell-type determination sweeps across the presumptive eye epithelium. This 'morphogenetic furrow' coordinates the epithelial cells' division cycle, shape and gene expression to produce evenly spaced neural cell clusters that will eventually form the adult ommatidia. As these clusters develop, they rotate inwards to face the eye's equator and establish tissue polarity. We have found that wingless is strongly expressed in the dorsal margin of the presumptive eye field, ahead of the morphogenetic furrow. We have shown that inactivation of Wingless results in the induction of an ectopic furrow that proceeds ventrally from the dorsal margin. This ectopic furrow is normal in most respects, however the clusters formed by it fail to rotate, and we propose a two-vector model to account for normal rotation and tissue polarity in the retina. A second consequence of this inactivation of Wingless is that the dorsal head is largely deleted. We have also found that patched loss-of-function mosaic clones induce circular ectopic morphogenetic furrows (consistent with the observations of other workers with the hedgehog, and PKA genes). We use such patched induced furrows to test the two-vector model for cluster rotation and tissue polarity.
在发育中的果蝇复眼中，一波模式形成和细胞类型确定的过程席卷假定的眼上皮。这种“形态发生沟”协调上皮细胞的分裂周期、形状和基因表达，以产生均匀间隔的神经细胞簇，这些细胞簇最终将形成成虫的小眼。随着这些细胞簇的发育，它们向内旋转以面对眼的赤道并建立组织极性。我们发现无翅基因在假定眼场的背缘强烈表达，先于形态发生沟。我们已经表明，无翅基因的失活导致从背缘腹侧延伸的异位沟的诱导。这个异位沟在大多数方面是正常的，然而由它形成的细胞簇无法旋转，我们提出了一个双向量模型来解释视网膜中的正常旋转和组织极性。无翅基因失活的第二个后果是背侧头部大部分缺失。我们还发现，功能丧失的patched镶嵌克隆诱导圆形异位形态发生沟（与其他研究刺猬基因和PKA基因的工作者的观察结果一致）。我们使用这种patched诱导的沟来测试细胞簇旋转和组织极性的双向量模型。
