Suppressor of hairless activates brachyury expression in the Ciona embryo.
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.
Corbo
J C
JC
Division of Genetics, University of California, 401 Barker Hall, Berkeley, California, 94720, USA.
Fujiwara
S
S
Levine
M
M
Di Gregorio
A
A
D000595:Amino Acid Sequence; D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D002938:Ciona intestinalis / Q000196:embryology*; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000032:analysis / Q000235:genetics*; D018274:Electroporation / Q000379:methods; D004742:Enhancer Elements, Genetic / Q000235:genetics; D005326:Fetal Proteins; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D006651:Histocytochemistry; D007763:Lac Operon / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009672:Notochord / Q000254:growth & development; D011506:Proteins / Q000235:genetics*; D051880:Receptors, Notch; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013489:Suppression, Genetic / Q000235:genetics*; D020825:T-Box Domain Proteins; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics*; D000098908:Brachyury Protein
D004268:DNA-Binding Proteins; D005326:Fetal Proteins; D008565:Membrane Proteins; D011506:Proteins; D051880:Receptors, Notch; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D020825:T-Box Domain Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D000098908:Brachyury Protein; C116155:Su(H) protein, Ciona intestinalis