Laminin levels regulate tissue migration and anterior-posterior polarity during egg morphogenesis in Drosophila

Summary Basement membranes (BMs) are specialized extracellular matrices required for tissue organization and organ formation. We study the role of laminin and its integrin receptor in the regulation of tissue migration during Drosophila oogenesis. Egg production in Drosophila involves the collective migration of follicle cells (FCs) over the BM to shape the mature egg. We show that laminin content in the BM increases with time, whereas integrin amounts in FCs do not vary significantly. Manipulation of integrin and laminin levels reveals that a dynamic balance of integrin-laminin amounts determines the onset and speed of FC migration. Thus, the interplay of ligand-receptor levels regulates tissue migration in vivo. Laminin depletion also affects the ultrastructure and biophysical properties of the BM and results in anterior-posterior misorientation of developing follicles. Laminin emerges as a key player in the regulation of collective cell migration, tissue stiffness, and the organization of anterior-posterior polarity in Drosophila.
Graphical Abstract
Highlights • Follicle cells with constant integrin levels face increasing laminin in fly oogenesis • Integrin-laminin levels fix the timing and speed of egg chamber rotation in vivo • Laminin depletion affects the ultrastructure and biophysical properties of the ECM • Laminin depletion results in anterior-posterior misorientation of developing follicles
Collective cell migration requires cell-ECM interactions. Using the fruit fly ovary, Díaz de la Loza et al. find that the ECM component laminin controls the onset and speed of epithelial sheet migration. Because laminin depletion also results in aberrant anterior-posterior polarity, laminin regulates coordinated migration during organogenesis and maintains axial polarity.