Disruption of the abdominal-B promoter tethering element results in a loss of long-range enhancer-directed Hox gene expression in Drosophila

PLoS One. 2011 Jan 21;6(1):e16283. doi: 10.1371/journal.pone.0016283.


There are many examples within gene complexes of transcriptional enhancers interacting with only a subset of target promoters. A number of molecular mechanisms including promoter competition, insulators and chromatin looping are thought to play a role in regulating these interactions. At the Drosophila bithorax complex (BX-C), the IAB5 enhancer specifically drives gene expression only from the Abdominal-B (Abd-B) promoter, even though the enhancer and promoter are 55 kb apart and are separated by at least three insulators. In previous studies, we discovered that a 255 bp cis-regulatory module, the promoter tethering element (PTE), located 5' of the Abd-B transcriptional start site is able to tether IAB5 to the Abd-B promoter in transgenic embryo assays. In this study we examine the functional role of the PTE at the endogenous BX-C using transposon-mediated mutagenesis. Disruption of the PTE by P element insertion results in a loss of enhancer-directed Abd-B expression during embryonic development and a homeotic transformation of abdominal segments. A partial deletion of the PTE and neighboring upstream genomic sequences by imprecise excision of the P element also results in a similar loss of Abd-B expression in embryos. These results demonstrate that the PTE is an essential component of the regulatory network at the BX-C and is required in vivo to mediate specific long-range enhancer-promoter interactions.

Publication types

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

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Drosophila melanogaster / metabolism*
  • Embryo, Nonmammalian
  • Enhancer Elements, Genetic*
  • Gene Expression Regulation, Developmental / genetics*
  • Gene Regulatory Networks
  • Genes, Homeobox / genetics*
  • Homeodomain Proteins / genetics
  • Promoter Regions, Genetic*
  • Transcription Initiation Site


  • Homeodomain Proteins