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

Abstract

Basement membranes (BMs) are specialized extra- cellular 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 produc- tion 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 in- creases 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 ultrastruc- ture and biophysical properties of the BM and results in anterior-posterior misorientation of developing follicles. Laminin emerges as a key player in the regu- lation of collective cell migration, tissue stiffness, and the organization of anterior-posterior polarity in Drosophila.