Héctor Herranz1, Xin Hong1,2 and Stephen M Cohen1,2
1 - Institute of Molecular and Cell Biology, 61 Biopolis Drive, Singapore 138673
2 - Department of Biological Sciences, National University of Singapore
Published in Current Biology, March 22, 2012. (Epub ahead of print)
The EGFR and Hippo signalling pathways control cell proliferation and apoptosis to promote tissue growth during development. Misregulation of these pathways is implicated in cancer. Our understanding of the mechanisms that integrate the activity of these pathways remains fragmentary. bantam microRNA is an important Hippo target in growth control. In this report we present evidence that bantam is regulated by the EGFR pathway, acting via Capicua. Thus, bantam appears to be a transcriptional target of both the EGFR and Hippo growth control pathways. Intriguingly, we also find that bantam acts in a feedback loop to limit Capicua expression. This provides a means to link signal propagation by the EGFR pathway to activity of the hippo pathway, and may play an important role in integration of these two pathways in growth control.
EGFR pathway regulates bantam expression.
(A-D) Confocal micrographs showing third instar wing discs expressing apG4 (anti-Gal4 shown in red). Genotypes: (A, C) apG4 controls. (B, D) apG4 UAS-EGFR. bantam-lacZ and bantam-sensor as indicated (green in merged image and grey in single channel at right).
(E, F) Confocal micrographs showing details of third instar wing discs containing clones of cells lacking EGFR (topF1, E), and Ras activity (RasΔ
C40b, F) marked by the absence of βGal protein (anti-βGal shown in red, grey). bantam sensor expression is shown in gray, and green in the merged image. Clones are marked by red arrowheads in bantam-sensor channel.
(G-I). Confocal micrographs showing third instar wing discs of the indicated genotypes. Discs were labelled with DAPI (red). Transgene expression was visualized by GFP fluorescence (green, in H), or dsRED fluorescence (green, in I).
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