Capulet and Slingshot share overlapping functions during Drosophila eye morphogenesis

Background: cap/capulet (capt),slingshot (ssh) and cofilin/twinstar (tsr) are actin-binding proteins that restrict actin polymerization. previously,it was shown that low resolution analyses of loss-of-function mutations in capt,ssh and tsr all show ectopic f-actin accumulation in various drosophila tissues. in contrast,rnai depletion of capt,tsr and ssh in drosophila s2 cells all affect actin-based lamella formation differently. whether loss of these three related genes might cause the same effect in the same tissue remains unclear. methods: loss-of-function mutant clones were generated using the marcm or eguf system whereas overexpression clones were generated using the flip-out system. immunostaining were then performed in eye imaginal discs with clones. frap was performed in cultured eye discs. results: here,we compared their loss-of-function phenotype at single-cell resolution,using a sheet of epithelial cells in the drosophila eye imaginal disc as a model system. surprisingly,we found that capt and ssh,but not tsr,mutant cells within and posterior to the morphogenetic furrow (mf) shared similar phenotypes. the capt/ssh mutant cells possessed: (1) hexagonal cell packing with discontinuous adherens junctions; and (2) largely complementary accumulation of excessive phosphorylated myosin light chain (p-mlc) and f-actin rings at the apical cortex. we further showed that the capt/ssh mutant phenotypes depended on the inactivation of protein kinase a (pka) and activation of rho. conclusions: although capt,ssh and tsr were reported to negatively regulate actin polymerization,we found that capt and ssh,but not tsr,share overlapping functions during eye morphogenesis. © 2012 lin et al.; licensee biomed central ltd.