Developmental rescue of Drosophila cephalic defects by the human Otx genes

Developmental rescue of Drosophila cephalic defects by the human Otx genes

^*Institute of Biological Sciences, University of Tsukuba, Tsukuba 305, Japan; ^†Zoological Institute, University of Basel, CH-4051 Basel, Switzerland; ^‡International Institute of Genetics and Biophysics, Consiglio Nazionale delle Ricerche, I-80125 Naples, Italy; and ^§Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, PA 19104

Communicated by Walter J. Gehring, University of Basel, Basel, Switzerland (received for review September 29, 1997)

Abstract

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.