Evolutionary conservation of a cell fate specification gene: the Hydra achaete-scute homolog has proneural activity in Drosophila.
Evolutionary conservation of a cell fate specification gene: the Hydra achaete-scute homolog has proneural activity in Drosophila.
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发表时间：
1995-12
期刊：
影响因子：
4.6
通讯作者：
Ann Grens;E. Mason;J. Marsh;H. Bode
中科院分区：
文献类型：
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作者：
Ann Grens;E. Mason;J. Marsh;H. Bode
碱性螺旋-环-螺旋转录因子的Achaete-scute家族成员参与脊椎动物和无脊椎动物的细胞命运特化。我们已经分离和特点的刺胞动物achaete盾状同源物，CnASH，从水螅，进化古老的后生动物的分支的代表。Hydra中存在一个Achaete-scute基因，预测基因产物的bHLH结构域与脊椎动物和果蝇Achaete-scute蛋白的氨基酸序列高度相似。在Hydra中，CnASH在间质细胞亚群以及间质细胞途径的分化中间体中表达。体外翻译的CnASH蛋白可以与果蝇bHLH蛋白Daughterless形成异源二聚体，并且这些二聚体以序列特异性方式结合共有的Achaete-scute DNA结合位点。CnASH在野生型三龄后期果蝇幼虫和蛹早期的异位表达导致异位感觉器官的形成，模仿内源性无毛鳞片基因的异位表达的效果。CnASH在无毛和盾形双突变体的果蝇中的表达提供了突变体表型的部分拯救，与通过果蝇基因的异位表达获得的拯救程度相当。这些结果表明，无毛鳞片型bHLH基因的细胞命运的规范，以及他们的行动方式，出现早，并已在后生动物进化过程中保守。
Members of the Achaete-scute family of basic helix-loop-helix transcription factors are involved in cell fate specification in vertebrates and invertebrates. We have isolated and characterized a cnidarian achaete-scute homolog, CnASH, from Hydra vulgaris, a representative of an evolutionarily ancient branch of metazoans. There is a single achaete-scute gene in Hydra, and the bHLH domain of the predicted gene product shares a high degree of amino acid sequence similarity with those of vertebrate and Drosophila Achaete-scute proteins. In Hydra, CnASH is expressed in a subset of the interstitial cells as well as differentiation intermediates of the nematocyte pathways. In vitro translated CnASH protein can form heterodimers with the Drosophila bHLH protein Daughterless, and these dimers bind to consensus Achaete-scute DNA binding sites in a sequence-specific manner. Ectopic expression of CnASH in wild-type late third instar Drosophila larvae and early pupae leads to the formation of ectopic sensory organs, mimicking the effect of ectopic expression of the endogenous achaete-scute genes. Expression of CnASH in flies that are achaete and scute double mutants gives partial rescue of the mutant phenotype, comparable to the degree of rescue obtained by ectopic expression of the Drosophila genes. These results indicate that the achaete-scute type of bHLH genes for cell fate specification, as well as their mode of action, arose early and have been conserved during metazoan evolution.