Jarman A P, Grau Y, Jan L Y, Jan Y N
Howard Hughes Medical Institute, University of California, San Francisco 94143.
Cell. 1993 Jul 2;73(7):1307-21. doi: 10.1016/0092-8674(93)90358-w.
In the Drosophila peripheral nervous system, proneural genes of the achaete-scute complex (ASC) are required for formation of the precursors of external sense organs but not of chordotonal organs. We report the isolation of a gene, atonal (ato), with evidence that it is a proneural gene for the formation of chordotonal organs. This gene is expressed in the proneural clusters and sense organ precursors that give rise to the embryonic and adult chordotonal, but not external sense, organs. Chordotonal organs are eliminated in embryos carrying chromosomal deficiencies that remove ato. Like the ASC products, ato protein contains a basic-helix-loop-helix region and heterodimerizes with daughterless protein to bind to E boxes. Moreover, ectopic expression of ato promotes the formation of extra sense organs. Despite similar proneural properties, we find that ectopic expression of the ASC genes promotes external sense organ formation exclusively, whereas ato promotes chordotonal organ formation preferentially. Thus, proneural genes are major determinants of neuronal identity.
在果蝇外周神经系统中，achaete - scute复合体（ASC）的原神经基因是形成外部感觉器官前体所必需的，但对于弦音器官的形成并非必需。我们报告了一个基因atonal（ato）的分离，有证据表明它是形成弦音器官的原神经基因。该基因在原神经簇和感觉器官前体中表达，这些前体产生胚胎期和成虫期的弦音器官而非外部感觉器官。携带缺失ato的染色体缺失的胚胎中弦音器官消失。与ASC产物一样，ato蛋白含有一个碱性 - 螺旋 - 环 - 螺旋区域，并与无女儿蛋白异源二聚化以结合E盒。此外，ato的异位表达促进额外感觉器官的形成。尽管具有相似的原神经特性，但我们发现ASC基因的异位表达仅促进外部感觉器官的形成，而ato优先促进弦音器官的形成。因此，原神经基因是神经元身份的主要决定因素。
