Cell competition, growth and size control in the Drosophila wing imaginal disc (original) (raw)
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RESEARCH ARTICLE| 15 November 2009
Supplemental Figure S1Fig. S1. Comparison of the expression of Dpp/Brk, Hpo/Warts and dMyc in M/+ and M+ territories. The Dpp/Brk gradient is an important growth regulator in the wing disc (Affolter and Basler, 2007; Burke and Basler, 1996; Martin et al., 2004; Schwank et al., 2008) and has also been implicated in cell competition (Moreno et al., 2002). To monitor Dpp activity levels in the overgrowing M+ clones, we used an antibody that recognizes the phosphorylated (active) form of the Dpp transducer Mad (pMad), an antibody against the Dpp target gene product Spalt (Barrio and de Celis, 2004) and also an anti-Brk antibody (Tanimoto et al., 2000). After examining a large number of clones we did not find any significant differences comparing M+ clones with surrounding M/+ cells. The Hpo/Warts pathway also plays an important role in growth, and there are some suggestions that it might have a role in cell competition (Tyler et al., 2007). Upregulation of Expanded and nuclear localisation of Yki are widely used as read-outs of the hippo pathway (Dong et al., 2007; Hamaratoglu et al., 2006). We have examined the expression of those three markers in M+ clones but failed to detect changes in their activity levels with respect to M/+ cells. Finally, we compared the dMyc activity levels in the two types of cells. This is an important comparison because it has been suggested that the confrontation of cells with dissimilar levels of dMyc is a key issue in triggering cell competition (de la Cova et al., 2004; Moreno and Basler, 2004). Using an anti-dMyc antibody we failed to find a difference between M+ and M/+ cells. (A,A′) pMad expression in a disc containing a large M+ clone, labelled by loss of GFP. There is no indication of a difference in pMad levels. (B,B′) The expression levels of Spalt (Sal) are not modified in M+ clones. (C-F′) Similarly, Brk (C,C′), dMyc (D,D′), Yorkie (E,E′) and Expanded (F,F′) are unaffected.
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Supplemental Figure S4Fig. S4. Additional results from computer simulations modifying different parameters. (A) Predictions for the average M+ territory of a M/+ discs containing a variable number of early M+ clones in the absence of cell competition. (B) Comparison of the computer prediction and the real data for late (72 hours BFP) clones. Note the very good agreement between the two sets of data. (C) Table of results of a number of simulations for various apoptosis parameters, the time needed for the disappearance of the apoptotic cell and the frequency of apoptotic cells at the borders of M+ clones. The number in the left column indicates the file number in the supplementary simulation folder in the http://bacterio.cbm.uam.es:8080/scherrera/simulations.zip file.References Affolter, M. and Basler, K. (2007). The Decapentaplegic morphogen gradient: from pattern formation to growth regulation. Nat. Rev. Genet.8, 663-674.Barrio, R. and de Celis, J. F. (2004). Regulation of spalt expression in the Drosophila wing blade in response to the Decapentaplegic signaling pathway. Proc. Natl. Acad. Sci. USA101, 6021-6026.Burke, R. and Basler, K. (1996). Dpp receptors are autonomously required for cell proliferation in the entire developing Drosophila wing. Development122, 2261-2269.Hamaratoglu, F., Willecke, M., Kango-Singh, M., Nolo, R., Hyun, E., Tao, C., Jafar-Nejad, H. and Halder, G. (2006). The tumour-suppressor genes NF2/Merlin and Expanded act through Hippo signalling to regulate cell proliferation and apoptosis. Nat. Cell Biol.8, 27-36.Martin, F. A., Perez-Garijo, A., Moreno, E. and Morata, G. (2004). The brinker gradient controls wing growth in Drosophila. Development131, 4921-4930.Schwank, G., Restrepo, S. and Basler, K. (2008). Growth regulation by Dpp: an essential role for Brinker and a non-essential role for graded signaling levels. Development135, 4003-4013.Tanimoto, H., Itoh, S., ten Dijke, P. and Tabata, T. (2000). Hedgehog creates a gradient of DPP activity in Drosophila wing imaginal discs. Mol. Cell5, 59-71.
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