Conversion of a dorsal-dependent silencer into an enhancer: Evidence for dorsal corepressors

Jin Jiang, Haini Cai, Qing Zhou, Michael Levine

Research output: Contribution to journalArticlepeer-review

116 Scopus citations


In Drosophila, the dorsal (dl) morphogen gradient initiates the differentiation of the embryonic mesoderm and neuroectoderm by activating the expression of regulatory genes (e.g. twist and snail) in a concentration-dependent manner, dl also functions as a represser that establishes the dorsal epidermis and amnioserosa by restricting regulatory genes such as dpp and zen to dorsal regions of the embryo. The ability of dl to function as both an activator and represser distinguishes it from the bicoid morphogen, which appears to function solely as an activator. In an effort to determine how dl functions as a represser we have performed a detailed characterization of a zen silencer element, called the VRE, which mediates ventral repression in response to the dl gradient. A minimal 110 bp VRE sequence is identified, which is able to silence the ventral expression of a heterologous promoter. This sequence contains two dl binding sites as well as binding sites for additional nuclear factors present in early embryos. Mutations in the latter binding sites convert the minimal VRE into an enhancer, which mediates transcriptional activation in ventral regions in response to dl. These results suggest that dl is intrinsically an activator, but is converted into a potent silencer when it interacts with neighboring corepressors.

Original languageEnglish (US)
Pages (from-to)3201-3209
Number of pages9
JournalEMBO Journal
Issue number8
StatePublished - 1993
Externally publishedYes

All Science Journal Classification (ASJC) codes

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


  • Corepressors
  • Dorsal
  • Drosophila
  • Morphogen
  • Silencing


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