Neuron, Vol. 14, 287-301, February, 1995

minibrain: A New Protein Kinase Family Involved in Postembryonic Neurogenesis in Drosophila

F. Tejedor (1,5), X. R. Zhu (2,5), E. Kaltenbach (3), A. Ackermann (2), A. Baumann (2,6), I. Canal (1), M. Heisenberg (4), K. F. Fischbach (3), and 0. Pongs (2)

1 Consejo Superior de Investigaciones Cientificas, Instituto Cajal, E-28002 Madrid, Spain
2 Zentrum für Molekulare Neurobiologie, Institut für Neurale Signalverarbeitung, D-2O246 Hamburg, Germany
3 lnstitut für Biologie Ill, D-79lO4 Freiburg, Germany
4 Theodor-Boveri-lnstitut für Biowissenschaften (Biozentrum), D-97074 Würzburg, Germany


The development of the adult central nervous system of Drosophila requires a precise and reproducible pattern of neuroblast proliferation during postembryonic neurogenesis. We show here that mutations in the minibrain (mnb) gene cause an abnormal spacing of neuroblasts in the outer proliferation center (opc) of larval brain, with the implication that mnb opc neuroblasts produce less neuronal progeny than do wild type. As a consequence, the adult mnb brain exhibits a specific and marked size reduction of the optic lobes and central brain hemispheres. The insufficient number of distinct neurons in mnb brains is correlated with specific abnormalities in visual and olfactory behavior. The mnb gene encodes a novel, cell type-specific serine-threonine protein kinase family that is expressed and required in distinct neuroblast proliferation centers during postembryonic neurogenesis. The mnb kinases share extensive sequence similarities with kinases involved in the regulation of cell division.