Torso signalling regulates terminal patterning in Drosophila by antagonising Groucho-mediated repression.
Patterning of the non-segmental termini of the Drosophila embryo depends on signalling via the Torso receptor tyrosine kinase (RTK). Activation of Torso at the poles of the embryo triggers restricted expression of the zygotic gap genes tailless (tll) and huckebein (hkb). In this paper, we show that the Groucho (Gro) corepressor acts in this process to confine terminal gap gene expression to the embryonic termini. Embryos lacking maternal gro activity display ectopic tll and hkb transcription; the former leads, in turn, to lack of abdominal expression of the Krüppel and knirps gap genes. We show that torso signalling permits terminal gap gene expression by antagonising Gro-mediated repression. Thus, the corepressor Gro is employed in diverse developmental contexts and, probably, by a variety of DNA-binding repressors.
Paroush
Z
Z
Imperial Cancer Research Fund, London, UK. zparoush@cc.huji.ac.il
Wainwright
S M
SM
Ish-Horowicz
D
D
D000005:Abdomen; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D019521:Body Patterning; D003433:Crosses, Genetic; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000378:metabolism*; D004330:Drosophila / Q000196:embryology*; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000502:physiology*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D007301:Insect Hormones / Q000096:biosynthesis; D008297:Male; D016296:Mutagenesis; D020794:Receptor Protein-Tyrosine Kinases / Q000502:physiology*; D012097:Repressor Proteins / Q000096:biosynthesis / Q000378:metabolism*; D015398:Signal Transduction; D016335:Zinc Fingers; D015053:Zygote / Q000502:physiology
D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D007301:Insect Hormones; D020794:Receptor Protein-Tyrosine Kinases; D012097:Repressor Proteins; C087725:Hkb protein, Drosophila; C074090:TLL protein, Drosophila; C091023:gro protein, Drosophila; C080148:tor protein, Drosophila