Altering the regulatory targets of the Deformed protein in Drosophila embryos by substituting the Abdominal-B homeodomain

Mech Dev. 1990 Dec;33(1):83-93. doi: 10.1016/0925-4773(90)90137-b.


The homeotic selector genes of Drosophila melanogaster encode transcriptional regulatory proteins that control the determination of different segmental fates. Binding of selector proteins to regulatory DNA sequences is mediated by an evolutionary conserved protein domain, the homeodomain. Although homeodomains encoded by the selector genes are very similar in their amino acid sequence and in vitro DNA-binding properties, here we provide additional evidence that the homeodomain is responsible for most of the regulatory specificity of the entire protein. A heat-shock promoter/selector gene was constructed that encodes a Deformed/Abdominal-B chimera in which the Abdominal-B homeodomain is substituted for that of Deformed. Expression of this chimeric protein throughout the embryo causes morphological transformation of anterior segments toward more posterior identities. A number of other homeotic selector genes, all normally repressed by Abdominal-B, are ectopically activated by the chimeric protein. These results support the hypothesis that the target specificity of similar homeodomain proteins is largely determined by the amino acid sequence of the homeodomain.

Publication types

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

MeSH terms

  • Abdomen / embryology
  • Animals
  • Animals, Genetically Modified
  • Base Sequence
  • Drosophila melanogaster / embryology
  • Drosophila melanogaster / genetics*
  • Gene Expression Regulation
  • Genes, Dominant
  • Genes, Homeobox*
  • Genes, Synthetic
  • Heat-Shock Proteins / genetics
  • Larva
  • Molecular Sequence Data
  • Morphogenesis / genetics
  • Recombinant Fusion Proteins / biosynthesis
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / physiology
  • Transcription Factors / genetics*
  • Transcription Factors / physiology
  • Transcription, Genetic


  • Heat-Shock Proteins
  • Recombinant Fusion Proteins
  • Transcription Factors