Date: 29 March 2016, Tuesday
Time: 9.30am
Venue: T-Lab Level 5 Seminar Room

by  Teng Xiang

Abstract

How epithelial apoptosis mechanically impacts the neighboring tissue is not fully understood. Live imaging of histoblast expansion, which is a coordinated tissue replacement process during Drosophila metamorphosis, show that apoptotic cells undergo rapid apical constriction. In the middle of this rapid apical constriction, adherens junctions (AJs) between apoptotic and non-dying cells become disengaged. Concurrently, tissue mechanical tension is transiently released. Contraction of a supra-cellular actomyosin cable forms in neighboring cells, brings the non-dying cells together and further reshapes tissue tension toward the completion of cell extrusion. By genetically blocking caspase activity, the characteristics of apoptotic cell extrusion, including the reduction in the levels of E-cad and the rapid apical constriction are diminished. Here, we conclude that a mechanical coordination between adhesion remodeling and tissue tension reshaping represents a mechanism of apoptotic cell extrusion.