Apical cell constriction during chicken lens placode invagination.
Vertebrate lens derives from invagination of the ectoderm that overlies optic vesicles. Epithelial invagination in many model systems is driven by apical cell constriction, mediated by actin and myosin II contraction regulated by GTPase RhoA. Here we investigate the possibility that chick lens placode invagination could also be driven by apical cell constriction and controlled by RhoA. We show that actin and myosin II are expressed at lens apical side during lens invagination. Actin polymerization inhibition by in ovo Cytochalasin D treatment prevents lens placode invagination, suggesting that lens placode invagination could be driven by apical cell constriction. RhoA GTPase is also expressed at apical portion of lens placode and during lens invagination. However, when we overexpressed by electroporation the dominant-negative RhoA in the pre-lens ectoderm invagination was not affected. Furthermore, dominant-negative RhoA didnt affect myosin II apical localization nor myosin II phosphorilation, indicating that in lens invagination this process is not regulated by GTPase RhoA.
Advisor:Chao Yun Irene Yan; Ricardo Guelerman Pinheiro Ramos; Marinilce Fagundes dos Santos; Chao Yun Irene Yan
School:Universidade de São Paulo
Source Type:Master's Thesis
Keywords:Apical cell constriction Epithelial invagination Morfogênese Morphogenesis Not muscle myosin II Placóide the lens RhoA
Date of Publication:11/06/2008