Yamamoto D
Mitsubishi Kasei Institute of Life Sciences, Tokyo, Japan.
Genetica. 1993;88(2-3):153-64. doi: 10.1007/BF02424472.
An ommatidium of a Drosophila compound eye contains eight photoreceptor cells, R1-R8. The fates of the photoreceptors are determined exclusively by inductive interactions between neuronal precursors in the cell cluster from which the ommatidium is formed. R7 induction has been extensively analysed at the molecular level. Activation of a membrane receptor tyrosine kinase (Sevenless) in the R7 precursor by a ligand (Bride of sevenless) present on the surface of R8 triggers a transduction cascade mediated by Ras, establishing the R7 fate of this cell. Other Sev-expressing cells are prevented from taking on the R7 fate by several different mechanisms. Pokkuri-mediated repression represents one such regulatory mechanism. The positive and negative signaling pathways operating in the fate determination of other photoreceptor cells are also discussed.
果蝇复眼中的一个小眼包含八个光感受器细胞，即R1 - R8。光感受器的命运完全由形成小眼的细胞簇中神经元前体之间的诱导相互作用决定。R7的诱导在分子水平上已得到广泛分析。R8表面存在的配体（七无之妻）激活R7前体中的膜受体酪氨酸激酶（七无），触发由Ras介导的转导级联反应，确定该细胞的R7命运。其他表达Sev的细胞通过几种不同机制被阻止具有R7命运。Pokkuri介导的抑制就是这样一种调节机制。还讨论了在其他光感受器细胞命运决定中起作用的正向和负向信号通路。
