The gap protein knirps mediates both quenching and direct repression in the Drosophila embryo

David N. Arnosti, Susan Gray, Scott Barolo, Jumin Zhou, Michael Levine

Research output: Contribution to journalArticlepeer-review

73 Scopus citations


Transcriptional repression is essential for establishing localized patterns of gene expression during Drosophila embryogenesis. Several mechanisms of repression have been proposed, including competition, quenching and direct repression of the transcription complex. Previous studies suggest that the knirps orphan receptor (kni) may repress transcription via competition, and exclude the binding of the bicoid (bcd) activator to an overlapping site in a target promoter. Here we present evidence that kni can quench, or locally inhibit, upstream activators within a heterologous enhancer in transgenic embryos. The range of kni repression is ~ 50-100 bp, so that neighboring enhancers in a modular promoter are free to interact with the transcription complex (enhancer autonomy). However, kni can also repress the transcription complex when bound in promoter-proximal regions. In this position, kni functions as a dominant repressor and blocks multiple enhancers in a modular promoter. Our studies suggest that short-range repression represents a flexible form of gene regulation, exhibiting enhancer- or promoter-specific effects depending on the location of repressor binding sites.

Original languageEnglish (US)
Pages (from-to)3659-3666
Number of pages8
JournalEMBO Journal
Issue number14
StatePublished - Jul 15 1996
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Biochemistry, Genetics and Molecular Biology
  • General Immunology and Microbiology
  • Molecular Biology
  • General Neuroscience


  • Drosophila embryo
  • Knirps
  • Nuclear receptor
  • Repression
  • Transcription


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