Preiss A, Hartley D A, Artavanis-Tsakonas S
Department of Biology, Yale University, New Haven, CT 06511.
EMBO J. 1988 Dec 1;7(12):3917-27. doi: 10.1002/j.1460-2075.1988.tb03278.x.
In Drosophila, the very first steps in neurogenesis appear to be controlled by a small group of zygotically acting genes termed the neurogenic loci. Mutations in any of these genes result in a misrouting of epidermal lineages into the neural pathway. Morphological and molecular studies suggest that the correct ectodermal differentiation is mediated by a cell-cell interaction mechanism and that at least some of the neurogenic loci are involved in this mechanism. The molecular analyses of the neurogenic loci Notch and Delta revealed that the putative gene products are large transmembrane proteins with homology to mammalian epidermal growth factor. We describe here a molecular analysis of Enhancer of split [E(spl)], a third neurogenic locus, which displays striking genetic interactions with both Notch and Delta, suggesting a close functional relationship of the respective gene products. We provide evidence for a single genetic complementation group corresponding to a single transcription unit which is necessary for wild-type E(spl) function. P-element-mediated transformation indicates that this transcription unit includes functions associated with both the dominant E(spl)D mutation and the recessive visible allele groucho, and is necessary for the correct differentiation of the embryonic nervous system.
在果蝇中，神经发生的最初步骤似乎由一小群合子作用基因控制，这些基因被称为神经源位点。这些基因中的任何一个发生突变都会导致表皮谱系错入神经途径。形态学和分子研究表明，正确的外胚层分化是由细胞间相互作用机制介导的，并且至少一些神经源位点参与了这一机制。对神经源位点Notch和Delta的分子分析表明，推测的基因产物是与哺乳动物表皮生长因子具有同源性的大型跨膜蛋白。我们在此描述对第三个神经源位点分裂增强子[E(spl)]的分子分析，它与Notch和Delta都表现出显著的遗传相互作用，表明各自基因产物之间存在密切的功能关系。我们提供证据表明，对应于单个转录单位的单一遗传互补群对于野生型E(spl)功能是必需的。P因子介导的转化表明，这个转录单位包括与显性E(spl)D突变和隐性可见等位基因gro相关的功能，并且对于胚胎神经系统的正确分化是必需的。
