Drosophila homeodomain protein dHb9 directs neuronal fate via crossrepressive and cell-nonautonomous mechanisms

Neuron. 2002 Jul 3;35(1):39-50. doi: 10.1016/s0896-6273(02)00743-2.

Abstract

Here we present the identification and characterization of dHb9, the Drosophila homolog of vertebrate Hb9, which encodes a factor central to motorneuron (MN) development. We show that dHb9 regulates neuronal fate by restricting expression of Lim3 and Even-skipped (Eve), two homeodomain (HD) proteins required for development of distinct neuronal classes. Also, dHb9 and Lim3 are activated independently of each other in a virtually identical population of ventrally and laterally projecting MNs. Surprisingly, dHb9 represses Lim3 cell nonautonomously in a subset of dorsally projecting MNs, revealing a novel role for intercellular signaling in the establishment of neuronal fate in Drosophila. Lastly, we provide evidence that dHb9 and Eve regulate each other's expression through Groucho-dependent crossrepression. This mutually antagonistic relationship bears similarity to the crossrepressive relationships between pairs of HD proteins that pattern the vertebrate neural tube.

Publication types

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

MeSH terms

  • Animals
  • Bacterial Proteins*
  • Basic Helix-Loop-Helix Transcription Factors
  • Cell Communication / genetics
  • Cell Differentiation / genetics
  • Cell Lineage / genetics*
  • Chemotaxis / genetics
  • Choristoma / genetics
  • Choristoma / metabolism
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism
  • Drosophila melanogaster / cytology
  • Drosophila melanogaster / embryology*
  • Drosophila melanogaster / genetics
  • Embryo, Nonmammalian / cytology
  • Embryo, Nonmammalian / embryology*
  • Embryo, Nonmammalian / metabolism
  • Female
  • Gene Expression Regulation, Developmental / genetics*
  • Growth Cones / metabolism
  • Growth Cones / ultrastructure
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism*
  • Male
  • Molecular Sequence Data
  • Motor Neurons / cytology
  • Motor Neurons / metabolism*
  • Mutation / genetics
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Nervous System / cytology
  • Nervous System / embryology*
  • Nervous System / metabolism
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*

Substances

  • Bacterial Proteins
  • Basic Helix-Loop-Helix Transcription Factors
  • DNA-Binding Proteins
  • Drosophila Proteins
  • Homeodomain Proteins
  • Nerve Tissue Proteins
  • Repressor Proteins
  • Transcription Factors
  • eve protein, Drosophila
  • exex protein, Drosophila
  • gro protein, Drosophila