Nagao T, Leuzinger S, Acampora D, Simeone A, Finkelstein R, Reichert H, Furukubo-Tokunaga K
Institute of Biological Sciences, University of Tsukuba, Tsukuba 305, Japan.
Proc Natl Acad Sci U S A. 1998 Mar 31;95(7):3737-42. doi: 10.1073/pnas.95.7.3737.
The molecular mechanisms of head development are a central question in vertebrate and invertebrate developmental biology. The anteriorly expressed homeobox gene otd in Drosophila and its homolog Otx in mouse are required for the early development of the most anterior part of the body, suggesting that a fundamental genetic program of cephalic development might be conserved between vertebrates and invertebrates. We have examined this hypothesis by introducing the human Otx genes into flies. By inducing expression of the human Otx homologs with a heat shock promoter, we found that both Otx1 and Otx2 functionally complement the cephalic defects of a fly otd mutant through specific activation and inactivation of downstream genes. Combined with previous morphological studies, these results are consistent with the view that a common molecular ground plan of cephalization was invented before the diversification of the protostome and the deuterostome in the course of metazoan evolution.
头部发育的分子机制是脊椎动物和无脊椎动物发育生物学中的核心问题。果蝇中在前部表达的同源异型盒基因otd及其在小鼠中的同源基因Otx是身体最前部早期发育所必需的，这表明脊椎动物和无脊椎动物之间可能保守着头部发育的基本遗传程序。我们通过将人类Otx基因导入果蝇来检验这一假设。通过用热休克启动子诱导人类Otx同源物的表达，我们发现Otx1和Otx2都通过下游基因的特异性激活和失活在功能上弥补了果蝇otd突变体的头部缺陷。结合先前的形态学研究，这些结果与以下观点一致：在后生动物进化过程中，原口动物和后口动物分化之前就已经存在一个共同的头部形成分子基础蓝图。
