Regulation by homeoproteins: a comparison of deformed-responsive elements

Genetics. 2000 Oct;156(2):677-86. doi: 10.1093/genetics/156.2.677.

Abstract

Homeotic genes of Drosophila melanogaster encode transcription factors that specify segment identity by activating the appropriate set of target genes required to produce segment-specific characteristics. Advances in understanding target gene selection have been hampered by the lack of genes known to be directly regulated by the HOM-C proteins. Here we present evidence that the gene 1.28 is likely to be a direct target of Deformed in the maxillary segment. We identified a 664-bp Deformed Response Element (1.28 DRE) that directs maxillary-specific expression of a reporter gene in transgenic embryos. The 1.28 DRE contains in vitro binding sites for Deformed and DEAF-1. The Deformed binding sites do not have the consensus sequence for cooperative binding with the cofactor Extradenticle, and we do not detect cooperative binding to these sites, though we cannot rule out an independent role for Extradenticle. Removing the four Deformed binding sites renders the 1.28 DRE inactive in vivo, demonstrating that these sites are necessary for activation of this enhancer element, and supporting the proposition that 1.28 is activated by Deformed. We show that the DEAF-1 binding region is not required for enhancer function. Comparisons of the 1.28 DRE with other known Deformed-responsive enhancers indicate that there are multiple ways to construct Deformed Response Elements.

Publication types

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

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Base Sequence
  • Binding Sites
  • Drosophila melanogaster / embryology
  • Drosophila melanogaster / genetics*
  • Embryo, Nonmammalian / physiology
  • Enhancer Elements, Genetic*
  • Gene Expression Regulation*
  • Genes, Homeobox*
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Recombinant Fusion Proteins / metabolism
  • Sequence Alignment
  • Sequence Homology, Nucleic Acid

Substances

  • Homeodomain Proteins
  • Recombinant Fusion Proteins