S-phase favours notch cell responsiveness in the Drosophila bristle lineage.
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.
Remaud
Sylvie
S
Université Pierre et Marie Curie, UMR 7622, Paris, France.
Audibert
Agnès
A
Gho
Michel
M
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
D002868:Chromosomal Proteins, Non-Histone; D029721:Drosophila Proteins; D051880:Receptors, Notch; D012097:Repressor Proteins; C452193:heterochromatin protein 1, Drosophila; C075878:ttk protein, Drosophila