BioProject

Cellular responses to signalling pathways are often highly dynamic, however most analyses of developmental signalling pathways focus on a single endpoint. More...

Cellular responses to signalling pathways are often highly dynamic, however most analyses of developmental signalling pathways focus on a single endpoint. We have analyzed the temporal changes in transcription following a short Notch activation treatment and related these to the recruitment of the Notch pathway transcription factor, CSL [Suppressor of Hairless, Su(H), in Drosophila], and to the state of RNA Polymerase II (Pol II) binding. A total of 154 genes showed significant differential expression over time and their expression profiles stratified into 14 clusters based on temporal and quantitative differences in their responses. These differences were partially reflected in the profiles of Pol II and Su(H) binding. However, neither could fully account for the different response profiles. Furthermore, the timing of the different responses was unaffected by more prolonged Notch activation. Instead our data suggest that regulatory relationships between genes that segregate into different response clusters can partially account for the stratification. Thus, feed-forward repression, where products of early responding Enhancer of split bHLH genes (E(spl)bHLH) inhibit expression of endogenous repressors, is one mechanism that explains the profile of genes that exhibit delayed up-regulation. E(spl)bHLH genes may therefore be responsible for co-ordinating the Notch response of a wide spectrum of other targets, explaining their critical functions in many developmental and disease contexts. Overall design: DmD8 cells were collected at 7 time points (0’, 10’, 20’, 30’, 40’, 60’ and 100’) after a 5 minute Notch stimulation as 3 independent replicates. Immunoprecipitation was performed with Pol II (Ser 2 and Ser 5 phosphorylated) antibody and compared to the total input DNA. Samples from replicates #1 and #3 were labelled with Cy5, and replicate #2 was labelled with Cy3 as a dye-swap. Less...