Ligoxygakis P, Yu S Y, Delidakis C, Baker N E
Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, and Department of Biology, University of Crete, Box 1527, GR 71110 Heraklion, Greece.
Development. 1998 Aug;125(15):2893-900. doi: 10.1242/dev.125.15.2893.
The Notch signalling pathway is involved in many processes where cell fate is decided. Previous work showed that Notch is required at successive steps during R8 specification in the Drosophila eye. Initially, Notch enhances atonal expression and promotes atonal function. After atonal autoregulation has been established, Notch signalling represses atonal expression during lateral specification. In this paper we investigate which known components of the Notch pathway are involved in each signalling process. Using clonal analysis we show that a ligand of Notch, Delta, is required along with Notch for both proneural enhancement and lateral specification, while the downstream components Suppressor-of-Hairless and Enhancer-of-Split are involved only in lateral specification. Our data point to a distinct signal transduction pathway during proneural enhancement by Notch. Using misexpression experiments we also show that particular Enhancer-of-split bHLH genes can differ greatly in their contribution to lateral specification.
Notch信号通路参与了许多决定细胞命运的过程。先前的研究表明，在果蝇眼睛的R8细胞特化过程中的连续步骤都需要Notch。最初，Notch增强无调蛋白的表达并促进其功能。在无调蛋白的自动调节建立之后，Notch信号在侧向特化过程中抑制无调蛋白的表达。在本文中，我们研究了Notch信号通路的哪些已知成分参与了每个信号传导过程。通过克隆分析，我们发现Notch的配体Delta与Notch一起对于神经原增强和侧向特化都是必需的，而下游成分无毛抑制因子和分裂增强子仅参与侧向特化。我们的数据表明在Notch介导的神经原增强过程中有一条独特的信号转导途径。通过错误表达实验我们还表明，特定的分裂增强子bHLH基因对侧向特化的贡献可能有很大差异。
