Ruiz-Gómez M, Modolell J
Centro de Biología Molecular, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
Genes Dev. 1987 Dec;1(10):1238-46. doi: 10.1101/gad.1.10.1238.
The achaete-scute gene complex (AS-C) is involved in the development of the central and peripheral (sensory chaetae, sensilla) nervous system. To assess the contribution of the different parts of the complex in the generation of the adult chaetae pattern, we have determined the phenotypes and molecular positions of the breakpoints of 74 terminal deficiencies of the X chromosome. According to these and previous data, the AS-C is organized, distally to proximally, as follows: the achaete region, with most of its DNA (10 kb) located upstream from the putative achaete (T5) gene; an intermediate region, approximately 18 kb long, whose deletion only weakly affects the scute function; and the scute region, with most of the DNA critical for its function extending 4-5 kb upstream and 50 kb downstream of the putative scute (T4) gene. The DNA extending far upstream of the T5 gene and downstream of the T4 gene may provide chromatin conformations adequate for efficient expression of these genes. However, in the case of the T4 gene, the available data suggest the presence of a small number of elements, scattered in the long downstream region, that would respond to topological cues and cis-activate this gene in specific anatomical regions.
achaete-scute基因复合体（AS-C）参与中枢和外周（感觉刚毛、感觉器）神经系统的发育。为了评估该复合体不同部分在成虫刚毛模式形成中的作用，我们确定了X染色体74个末端缺失断点的表型和分子位置。根据这些以及先前的数据，AS-C从远端到近端的组织方式如下：achaete区域，其大部分DNA（10 kb）位于假定的achaete（T5）基因上游；一个中间区域，约18 kb长，其缺失仅对scute功能有微弱影响；以及scute区域，其功能关键的大部分DNA在假定的scute（T4）基因上游延伸4 - 5 kb，在下游延伸50 kb。T5基因上游远处和T4基因下游延伸的DNA可能提供适合这些基因高效表达的染色质构象。然而，就T4基因而言，现有数据表明在长下游区域分散存在少量元件，这些元件会响应拓扑线索并在特定解剖区域顺式激活该基因。
