Essential roles of Drosophila RhoA in the regulation of neuroblast proliferation and dendritic but not axonal morphogenesis

Neuron. 2000 Feb;25(2):307-16. doi: 10.1016/s0896-6273(00)80896-x.


The pleiotropic functions of small GTPase Rho present a challenge to its genetic analysis in multicellular organisms. We report here the use of the MARCM (mosaic analysis with a repressible cell marker) system to analyze the function of RhoA in the developing Drosophila brain. Clones of cells homozygous for null RhoA mutations were specifically labeled in the mushroom body (MB) neurons of mosaic brains. We found that RhoA is required for neuroblast (Nb) proliferation but not for neuronal survival. Surprisingly, RhoA is not required for MB neurons to establish normal axon projections. However, neurons lacking RhoA overextend their dendrites, and expression of activated RhoA causes a reduction of dendritic complexity. Thus, RhoA is an important regulator of dendritic morphogenesis, while distinct mechanisms are used for axonal morphogenesis.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animal Structures / cytology
  • Animal Structures / growth & development
  • Animals
  • Antimetabolites
  • Axons / metabolism*
  • Bromodeoxyuridine
  • Cell Differentiation / physiology
  • Cell Division / physiology
  • Cell Size / physiology
  • Dendrites / metabolism*
  • Drosophila
  • Gene Expression Regulation, Developmental
  • Mutation / physiology
  • Neurons / ultrastructure*
  • Phenotype
  • Stem Cells / ultrastructure*
  • rhoA GTP-Binding Protein / genetics
  • rhoA GTP-Binding Protein / metabolism*


  • Antimetabolites
  • rhoA GTP-Binding Protein
  • Bromodeoxyuridine