Suppressor of hairless activates brachyury expression in the Ciona embryo

Dev Biol. 1998 Nov 15;203(2):358-68. doi: 10.1006/dbio.1998.9067.


The Ciona Brachyury gene (Ci-Bra) is regulated, in part, by a 434-bp enhancer that mediates restricted expression in the notochord. Here we present evidence that a Ciona Suppressor of Hairless ¿Ci-Su(H)¿ protein functions as an activator of this enhancer. Point mutations that reduce the binding of a GST/Ci-Su(H) fusion protein in vitro diminish the expression of mutagenized Ci-Bra/lacZ transgenes in electroporated embryos. Overexpression of a Ci-Su(H) fusion protein containing the Drosophila Hairy repression domain interferes with notochord differentiation, producing mutant tadpoles with shortened tails. Expression of a constitutively activated Xotch receptor in the notochord, endoderm, and CNS also alters tail morphogenesis. These results suggest that a Notch-Su(H) pathway might participate in notochord differentiation in Ciona.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Differentiation / genetics
  • Ciona intestinalis / embryology*
  • Cloning, Molecular
  • DNA-Binding Proteins / analysis
  • DNA-Binding Proteins / genetics*
  • Electroporation / methods
  • Enhancer Elements, Genetic / genetics
  • Fetal Proteins*
  • Gene Expression Regulation, Developmental / genetics*
  • Histocytochemistry
  • Lac Operon / genetics
  • Membrane Proteins / genetics
  • Molecular Sequence Data
  • Notochord / growth & development
  • Proteins / genetics*
  • Receptors, Notch
  • Recombinant Fusion Proteins / genetics
  • Repressor Proteins / genetics
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Suppression, Genetic / genetics*
  • T-Box Domain Proteins*
  • Trans-Activators*
  • Transcription Factors / genetics*


  • DNA-Binding Proteins
  • Fetal Proteins
  • Membrane Proteins
  • Proteins
  • Receptors, Notch
  • Recombinant Fusion Proteins
  • Repressor Proteins
  • Su(H) protein, Ciona intestinalis
  • T-Box Domain Proteins
  • Trans-Activators
  • Transcription Factors
  • Brachyury protein