Wehrli M, Tomlinson A
Department of Genetics and Development, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA.
Development. 1998 Apr;125(8):1421-32. doi: 10.1242/dev.125.8.1421.
The Drosophila retina is made from hundreds of asymmetric subunit ommatidia arranged in a crystalline-like array with each unit shaped and oriented in a precise way. One explanation for the precise cellular arrangements and orientations of the ommatidia is that they respond to two axes of polarized information present in the plane of the retinal epithelium. Earlier work showed that one of these axes lies in the anterior/posterior(A/P) direction and that the polarizing influence is closely associated with the sweep of the Hedgehog-dependent morphogenetic wave. Here we present evidence for a second and orthogonal axis of polarity, and show that it can be functionally separated from the A/P axis. Further, we show that the polarizing information acting in this equatorial/polar axis (Eq/Pl) is established in at least two steps - the activity of one signaling molecule functions to establish the graded activity of a second signal.
果蝇的视网膜由数百个不对称的亚基小眼组成，这些小眼排列成晶体状阵列，每个单元都以精确的方式塑造和定向。小眼精确的细胞排列和定向的一种解释是，它们对存在于视网膜上皮平面中的两个偏振信息轴做出反应。早期的研究表明，其中一个轴位于前后（A/P）方向，并且偏振影响与依赖于刺猬信号通路的形态发生波的扫描密切相关。在这里，我们提供了第二个正交极性轴的证据，并表明它在功能上可以与A/P轴分离。此外，我们表明，作用于这个赤道/极轴（Eq/Pl）的偏振信息至少分两步建立——一种信号分子的活性起到建立第二种信号的梯度活性的作用。
