abdominal A specifies one cell type in Drosophila by regulating one principal target gene

Development. 2002 Jun;129(12):2957-63.


The Hox/homeotic genes encode transcription factors that generate segmental diversity during Drosophila development. At the level of the whole animal, they are believed to carry out this role by regulating a large number of downstream genes. Here we address the unresolved issue of how many Hox target genes are sufficient to define the identity of a single cell. We focus on the larval oenocyte, which is restricted to the abdomen and induced in response to a non-cell autonomous, transient and highly selective input from abdominal A (abdA). We use Hox mutant rescue assays to demonstrate that this function of abdA can be reconstituted by providing Rhomboid (Rho), a processing factor for the EGF receptor ligand, secreted Spitz. Thus, in order to make an oenocyte, abdA regulates just one principal target, rho, that acts at the top of a complex hierarchy of cell-differentiation genes. These studies strongly suggest that, in at least some contexts, Hox genes directly control only a few functional targets within each nucleus. This raises the possibility that much of the overall Hox downstream complexity results from cascades of indirect regulation and cell-to-cell heterogeneity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abdomen / embryology
  • Abdomen / growth & development
  • Animals
  • Antennapedia Homeodomain Protein
  • Arabidopsis Proteins*
  • Drosophila / embryology
  • Drosophila / genetics
  • Drosophila / growth & development*
  • Drosophila Proteins*
  • Embryo, Nonmammalian
  • Epidermal Growth Factor*
  • Gene Expression Regulation, Developmental*
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism
  • Insect Proteins / genetics
  • Insect Proteins / metabolism*
  • Larva
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Mutation
  • Nuclear Proteins*
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism


  • Antennapedia Homeodomain Protein
  • Antp protein, Drosophila
  • Arabidopsis Proteins
  • Drosophila Proteins
  • Homeodomain Proteins
  • Insect Proteins
  • Membrane Proteins
  • Nuclear Proteins
  • Plant Proteins
  • Rho protein, Drosophila
  • SCR protein, Arabidopsis
  • Stet protein, Drosophila
  • Transcription Factors
  • exd protein, Drosophila
  • abd-A protein, Drosophila
  • spi protein, Drosophila
  • Epidermal Growth Factor