Abstract
During development, epithelia must coordinate morphogenesis with neighboring cell lineages to drive structural remodeling of organ systems. How adhesion between epithelial and other cell types is established and maintained remains poorly understood. Using the Drosophila ovary as an in vivo model, we show that anterior follicle cells (AFCs) undergo epithelial plasticity to establish and maintain adhesion with germline nurse cells during late oogenesis. As AFCs spread over the nurse-cell compartment, adherens junctions disassemble, and E-cadherin, together with junctional partners, reorganizes into apical "spot junctions." Formation of these junctions requires E-cadherin in both follicle and germline cells and is promoted by the expansion of the AFC apical surface. Quantitative imaging reveals that spot junctions form a uniformly spaced lattice that remains stable as the AFC-nurse cell interface enlarges. Functionally, these E-cadherin-based junctions are essential to maintain soma-germline adhesion, enabling full envelopment and clearance of nurse cell remnants by AFCs during late oogenesis. Our findings uncover a mechanism by which an epithelium repurposes its apical membrane into a specialized adhesive surface, providing a paradigm for the emergence of interlineage adhesion in developing tissues.
