Phillips R G, Warner N L, Whittle J R
School of Biological Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, United Kingdom.
Dev Biol. 1999 Mar 1;207(1):150-62. doi: 10.1006/dbio.1998.9149.
Wnt and Decapentaplegic cell signaling pathways act synergistically in their contribution to macrochaete (sense organ) patterning on the notum of Drosophila melanogaster. The Wingless-signaling pathway was ectopically activated by removing Shaggy activity (the homologue of vertebrate glycogen synthase kinase 3) in mosaics. Proneural activity is asymmetric within the Shaggy-deficient clone of cells and shows a fixed "polarity" with respect to body axis, independent of the precise location of the clone. This asymmetric response indicates the existence in the epithelium of a second signal, which we suggest is Decapentaplegic. Ectopic expression of Decapentaplegic induces extra macrochaetes only in cells which also receive the Wingless signal. Activation of Hedgehog signaling generates a long-range signal which can promote macrochaete formation in the Wingless activity domain. This signal depends upon decapentaplegic function. Autonomous activation of the Wingless signal response in cells causes them to attenuate or sequester this signal. Our results suggest a novel patterning mechanism which determines sense organ positioning in Drosophila.
Wnt和Decapentaplegic细胞信号通路在果蝇背板上对大刚毛（感觉器官）模式形成的作用中协同发挥作用。通过在嵌合体中去除Shaggy活性（脊椎动物糖原合酶激酶3的同源物）异位激活无翅信号通路。神经前体活性在缺乏Shaggy的细胞克隆中是不对称的，并且相对于身体轴显示出固定的“极性”，与克隆的精确位置无关。这种不对称反应表明上皮中存在第二种信号，我们认为是Decapentaplegic。Decapentaplegic的异位表达仅在也接收无翅信号的细胞中诱导额外的大刚毛。Hedgehog信号的激活产生一种远程信号，其可以促进无翅活性域中的大刚毛形成。该信号取决于Decapentaplegic功能。细胞中无翅信号反应的自主激活导致它们减弱或隔离该信号。我们的结果提示了一种新的模式形成机制，其决定了果蝇中感觉器官的定位。
