Williams R, Lendahl U, Lardelli M
Department of Cell and Molecular Biology, Medical Nobel Institute, Karolinska Institute, Stockholm, Sweden.
Mech Dev. 1995 Nov;53(3):357-68. doi: 10.1016/0925-4773(95)00451-3.
The Drosophila Notch gene encodes a transmembrane receptor involved in the regulation of cell fate. It exerts its effect by lateral specification, inductive signaling and is also important for cell adhesion and axonal pathfinding. In this report we analyse the expression of the three mammalian Notch homologues during early mouse development by in situ hybridization. The Notch 1, 2 and 3 genes show dynamic and complex expression patterns, in particular during gastrulation and somitogenesis and in early nervous system formation. During gastrulation, the Notch genes are expressed in non-overlapping, successive patterns. Notch 3 is widely expressed in both ectoderm and mesoderm. Notch 2 is then expressed in the node, notochord and neural groove while Notch 1 becomes highly expressed in presomitic mesoderm. As somitogenesis begins, Notch 2 expression is activated in newly forming somites while Notch 3 is activated in mature somites. Various neural crest cell populations and ectodermal placode cells can be defined by expression of specific combinations of Notch genes. All three Notch genes are expressed within cells of the dorsal neural tube at E9.5, although neural crest cells that have begun migrating all show distinct patterns of Notch expression. Finally, Notch 1 expression is observed not only in placodes, but also in cells migrating from placodes to the site of the ganglia anlagen. This expression pattern may be analogous to Notch expression in the peripheral nervous system of Drosophila, suggesting that mammalian Notch genes may also be involved in axonal pathfinding.
果蝇Notch基因编码一种参与细胞命运调控的跨膜受体。它通过侧向特化、诱导信号传导发挥作用，对细胞黏附和轴突导向也很重要。在本报告中，我们通过原位杂交分析了三种哺乳动物Notch同源物在小鼠早期发育过程中的表达情况。Notch 1、2和3基因呈现出动态且复杂的表达模式，尤其是在原肠胚形成、体节发生以及早期神经系统形成过程中。在原肠胚形成期间，Notch基因以不重叠的连续模式表达。Notch 3在外胚层和中胚层中广泛表达。随后，Notch 2在节点、脊索和神经沟中表达，而Notch 1在体节形成前的中胚层中高度表达。随着体节发生开始，Notch 2在新形成的体节中被激活，而Notch 3在成熟体节中被激活。特定Notch基因组合的表达可定义各种神经嵴细胞群体和外胚层基板细胞。在E9.5时，所有三种Notch基因都在背神经管细胞中表达，尽管已经开始迁移的神经嵴细胞都显示出不同的Notch表达模式。最后，不仅在基板中观察到Notch 1的表达，而且在从基板迁移到神经节原基部位的细胞中也观察到Notch 1的表达。这种表达模式可能类似于果蝇外周神经系统中的Notch表达，表明哺乳动物Notch基因也可能参与轴突导向。
