Patel N H, Martin-Blanco E, Coleman K G, Poole S J, Ellis M C, Kornberg T B, Goodman C S
Howard Hughes Medical Institute, Department of Biochemistry, University of California, Berkeley 94720.
Cell. 1989 Sep 8;58(5):955-68. doi: 10.1016/0092-8674(89)90947-1.
engrailed is a homeobox gene that has an important role in Drosophila segmentation. Genes homologous to engrailed have been identified in several other organisms. Here we describe a monoclonal antibody that recognizes a conserved epitope in the homeodomain of engrailed proteins of a number of different arthropods, annelids, and chordates; we use this antibody to isolate the grasshopper engrailed gene. In Drosophila embryos, the antibody reveals engrailed protein in the posterior portion of each segment during segmentation, and in a segmentally reiterated subset of neuronal cells during neurogenesis. Other arthropods, including grasshopper and two crustaceans, have similar patterns of engrailed expression. However, these patterns of expression are not shared by the annelids or chordates we examined. Our results provide the most comprehensive view that has been obtained of how expression patterns of a regulatory gene vary during evolution. On the basis of these patterns, we suggest that engrailed is a gene whose ancestral function was in neurogenesis and whose function was co-opted during the evolution of segmentation in the arthropods, but not in the annelids and chordates.
engrailed是一种同源异型框基因，在果蝇体节形成过程中起重要作用。在其他几种生物中也鉴定出了与engrailed同源的基因。在此，我们描述了一种单克隆抗体，它能识别多种不同节肢动物、环节动物和脊索动物的engrailed蛋白同源结构域中的一个保守表位；我们用这种抗体分离出了蝗虫的engrailed基因。在果蝇胚胎中，该抗体在体节形成期间的每个体节后部以及神经发生期间的一部分按节重复的神经元细胞中显示出engrailed蛋白。其他节肢动物，包括蝗虫和两种甲壳类动物，具有类似的engrailed表达模式。然而，我们所研究的环节动物和脊索动物并没有共享这些表达模式。我们的结果提供了关于一个调控基因的表达模式在进化过程中如何变化的最全面的观点。基于这些模式，我们认为engrailed是一个基因，其祖先功能是在神经发生中，并且其功能在节肢动物体节进化过程中被征用，但在环节动物和脊索动物中并非如此。
