Diaz-Benjumea F J, Cohen S M
Differentiation Programme, European Molecular Biology Laboratory, Heidelberg, Germany.
Development. 1994 Jun;120(6):1661-70. doi: 10.1242/dev.120.6.1661.
The secreted glycoproteins encoded by Wnt genes are thought to function as intercellular signaling molecules which convey positional information. Localized expression of Wingless protein is required to specify the fate of ventral cells in the developing Drosophila leg. We report here that Wingless acts through inactivation of the shaggy/zeste white 3 protein kinase to specify ventral cell fate in the leg. Ectopic expression of Wingless outside its normal ventral domain has been shown reorganize the dorsal-ventral axis of the leg in a non-autonomous manner. Using genetic mosaics, we show that cells that lack shaggy/zeste white 3 activity can influence the fate of neighboring cells to reorganize dorsal-ventral pattern in the leg, in the same manner as Wingless-expressing cells. Therefore, clones of cells that lack shaggy/zeste white 3 activity exhibit all of the organizer activity previously attributed to Wingless-expressing cells, but do so without expressing wingless. We also show that the organizing activity of ventral cells depends upon the location of the clone along the dorsal-ventral axis. These findings suggest that Wingless protein does not function as a morphogen in the dorsal-ventral axis of the leg.
Wnt基因编码的分泌型糖蛋白被认为作为传递位置信息的细胞间信号分子发挥作用。无翅蛋白的局部表达对于确定发育中的果蝇腿部腹侧细胞的命运是必需的。我们在此报告，无翅蛋白通过使蓬乱/小体白色3蛋白激酶失活来确定腿部腹侧细胞的命运。已证明无翅蛋白在其正常腹侧区域之外的异位表达以非自主方式重组腿部的背腹轴。利用遗传镶嵌体，我们表明缺乏蓬乱/小体白色3活性的细胞能够以与表达无翅蛋白的细胞相同的方式影响相邻细胞的命运，从而重组腿部的背腹模式。因此，缺乏蓬乱/小体白色3活性的细胞克隆表现出先前归因于表达无翅蛋白的细胞的所有组织者活性，但这样做时并不表达无翅蛋白。我们还表明腹侧细胞的组织活性取决于克隆沿背腹轴的位置。这些发现表明无翅蛋白在腿部的背腹轴中不作为形态发生素发挥作用。
