The activity of Drosophila Hairless is required in pupae but not in embryos to inhibit Notch signal transduction.
Drosophila Hairless (H) encodes a negative regulator of Notch signalling. H activity antagonizes Notch (N) signalling during bristle development at the pupal stage. We show here by clonal analysis that H acts by inhibiting signal transduction rather than by promoting signal production, during both selection of microchaete precursors in the notum and vein cell differentiation in the wing. Allele-specific interactions further suggest that H inhibits Notch signal transduction by interacting directly with Suppressor of Hairless. Unexpectedly, this regulatory function of H appears to be essential only during imaginal development. Using a null allele of H that corresponds to a deletion of the H coding sequence, we show that embryos devoid of both maternal and zygotic gene products develop similarly to wild-type embryos. Thus, H activity is not strictly required to regulate N-mediated cell fate choices in the embryo.
Schweisguth
F
F
Institut Jacques Monod, CNRS-Université Paris 7, 2, place Jussieu, F-75251 Paris Cedex 05, France.
Lecourtois
M
M
D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D004330:Drosophila / Q000196:embryology* / Q000235:genetics* / Q000254:growth & development; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian; D005260:Female; D019476:Insect Proteins / Q000235:genetics* / Q000502:physiology*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D009154:Mutation; D011679:Pupa; D051880:Receptors, Notch; D012097:Repressor Proteins / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics*; D013234:Stem Cells / Q000502:physiology; D014157:Transcription Factors; D014921:Wings, Animal / Q000166:cytology / Q000254:growth & development
D029721:Drosophila Proteins; D019476:Insect Proteins; D008565:Membrane Proteins; C497759:N protein, Drosophila; D051880:Receptors, Notch; D012097:Repressor Proteins; C088731:Su(H) protein, Drosophila; D014157:Transcription Factors; C076560:H protein, Drosophila