Browsing by Issue Date, starting with "2011-09"
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- Homeostasis of the Drosophila adult retina by actin-capping protein and the Hippo pathwayPublication . Brás-Pereira, C.; Zhang, T.; Pignoni, F.; Janody, F.The conserved Hippo signaling pathway regulates multiple cellular events, including tissue growth, cell fate decision and neuronal homeostasis. While the core Hippo kinase module appears to mediate all the effects of the pathway, various upstream inputs have been identified depending on tissue context. We have recently shown that, in the Drosophila wing imaginal disc, actin-Capping Protein and Hippo pathway activities inhibit F-actin accumulation. In turn, the reduction in F-actin sustains Hippo pathway activity, preventing Yorkie nuclear translocation and the upregulation of proliferation and survival genes. Here, we investigate the role of Capping Protein in growth-unrelated events controlled by the Hippo pathway. We provide evidence that loss of Capping Protein induces degeneration of the adult Drosophila retina through misregulation of the Hippo pathway. We propose a model by which F-actin dynamics might be involved in all processes that require the activity of the core Hippo kinase module.
- Requirements for Mediator Complex Subunits Distinguish Three Classes of Notch Target Genes at the Drosophila Wing MarginPublication . Janody, F.; Treisman, J.E.Spatial and temporal gene regulation relies on a combinatorial code of sequence-specific transcription factors that must be integrated by the general transcriptional machinery. A key link between the two is the mediator complex, which consists of a core complex that reversibly associates with the accessory kinase module. We show here that genes activated by Notch signaling at the dorsal-ventral boundary of the Drosophila wing disc fall into three classes that are affected differently by the loss of kinase module subunits. One class requires all four kinase module subunits for activation, while the others require only Med12 and Med13, either for activation or for repression. These distinctions do not result from different requirements for the Notch coactivator Mastermind or the corepressors Hairless and Groucho. We propose that interactions with the kinase module through distinct cofactors allow the DNA-binding protein Suppressor of Hairless to carry out both its activator and repressor functions.