Anderson M G, Perkins G L, Chittick P, Shrigley R J, Johnson W A
Department of Physiology and Biophysics, University of Iowa, College of Medicine, Iowa City 52242.
Genes Dev. 1995 Jan 1;9(1):123-37. doi: 10.1101/gad.9.1.123.
The Drosophila drifter (dfr) gene, previously referred to as Cf1a, encodes a POU-domain DNA-binding protein implicated as a neuron-specific regulator in the developing central nervous system (CNS). We have isolated full-length dfr cDNA clones that encode a 46-kD protein containing the conserved POU-domain DNA-binding domain. The use of alternate polyadenylation sites produces two dfr mRNA transcripts that are first expressed in stage 10 embryos at 5- to 6-hr of development. A specific anti-dfr polyclonal antiserum generated against a dfr-glutathione S-transferase fusion protein recognizes a 46-kD protein on Western blots and has been used to analyze the cell-specific distribution of dfr protein during embryonic development. dfr protein is distributed in a complex expression pattern including the tracheal system, the middle pair of midline glia, and selected CNS neurons. We have carried out a genetic characterization of the dfr locus, previously localized to region 65D of the third chromosome, by generating a series of overlapping deficiencies between 65A and 65E1 that were used to isolate dfrE82, an EMS-induced lethal allele. Analysis of dfrE82 mutant embryos shows a disruption of the developing tracheal tree as well as commissural defects in the developing CNS. Based on an examination of a cell-specific marker for tracheal cells and midline glia, these defects appear to be caused by a failure of these cells to follow their characteristic routes of migration. The dfrE82 tracheal phenotype is rescued by a dfr minigene present as a P-element transposon expressing wild-type dfr protein in tracheal cells. These results suggest that the dfr protein plays a fundamental role in the differentiation of tracheal cells and midline glia possibly by regulating the expression of essential cell-surface proteins required for cell-cell interactions involved in directed cell migrations.
果蝇漂流者（dfr）基因，以前称为Cf1a，编码一种POU结构域DNA结合蛋白，被认为是发育中的中枢神经系统（CNS）中的神经元特异性调节因子。我们分离出了全长dfr cDNA克隆，其编码一种46-kD的蛋白质，该蛋白质含有保守的POU结构域DNA结合域。使用交替的聚腺苷酸化位点产生两种dfr mRNA转录本，它们在发育5至6小时的10期胚胎中首次表达。针对dfr-谷胱甘肽S-转移酶融合蛋白产生的特异性抗dfr多克隆抗血清在蛋白质印迹上识别出一种46-kD的蛋白质，并已用于分析胚胎发育过程中dfr蛋白的细胞特异性分布。dfr蛋白以复杂的表达模式分布，包括气管系统、中线神经胶质细胞的中间对以及选定的中枢神经系统神经元。我们通过在65A和65E1之间产生一系列重叠缺失来对dfr基因座进行遗传特征分析，该基因座先前定位于第三条染色体的65D区域，这些缺失用于分离dfrE82，一种EMS诱导的致死等位基因。对dfrE82突变胚胎的分析显示发育中的气管树受到破坏以及发育中的中枢神经系统出现连合缺陷。基于对气管细胞和中线神经胶质细胞的细胞特异性标记物的检查，这些缺陷似乎是由这些细胞未能遵循其特征性迁移途径引起的。dfrE82气管表型由作为P元件转座子存在的dfr小基因挽救，该转座子在气管细胞中表达野生型dfr蛋白。这些结果表明，dfr蛋白可能通过调节参与定向细胞迁移的细胞间相互作用所需的必需细胞表面蛋白的表达，在气管细胞和中线神经胶质细胞的分化中起基本作用。
