title: S-phase favours notch cell responsiveness in the Drosophila bristle lineage.
abstract: We have studied cell sensitivity to Notch pathway signalling throughout the cell cycle. As model system, we used the Drosophila bristle lineage where at each division N plays a crucial role in fate determination. Using in vivo imaging, we followed this lineage and activated the N-pathway at different moments of the secondary precursor cell cycle. We show that cells are more susceptible to respond to N-signalling during the S-phase. Thus, the period of heightened sensitivity coincided with the period of the S-phase. More importantly, modifications of S-phase temporality induced corresponding changes in the period of the cell's reactivity to N-activation. Moreover, S-phase abolition was correlated with a decrease in the expression of tramtrack, a downstream N-target gene. Finally, N cell responsiveness was modified after changes in chromatin packaging. We suggest that high-order chromatin structures associated with the S-phase create favourable conditions that increase the efficiency of the transcriptional machinery with respect to N-target genes.
authors.affiliation: Université Pierre et Marie Curie, UMR 7622, Paris, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Remaud
authors.forename: Agnès
authors.initials: A
authors.lastname: Audibert
authors.forename: Michel
authors.initials: M
authors.lastname: Gho
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D002455:Cell Division / Q000235:genetics / Q000502:physiology; D002461:Cell Line, Transformed; D019070:Cell Lineage / Q000235:genetics*; D042002:Chromatin Assembly and Disassembly / Q000235:genetics; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000502:physiology; D004261:DNA Replication / Q000235:genetics / Q000502:physiology; D004330:Drosophila / Q000235:genetics* / Q000502:physiology; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D008954:Models, Biological; D011679:Pupa / Q000166:cytology; D051880:Receptors, Notch / Q000235:genetics / Q000502:physiology*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D016196:S Phase / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D013997:Time Factors; D014158:Transcription, Genetic / Q000502:physiology
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D029721:Drosophila Proteins; D051880:Receptors, Notch; D012097:Repressor Proteins; C452193:heterochromatin protein 1, Drosophila; C075878:ttk protein, Drosophila