Prof Denise Montell
UC Santa Barbara
What do cells do when they get where they are going?
During embryonic development and cancer metastasis, migratory cells must establish stable connections with new partners at their destinations. Here we establish the Drosophila border cells as a model for this multistep process. During oogenesis, border cells delaminate from the follicular epithelium and migrate. When they reach their target, the oocyte, they undergo a stereotypical series of steps to adhere to it, then connect with another migrating epithelium. We identify gap-junction-forming Innexin proteins as critical. Surprisingly, the channel function is dispensable. Instead, Innexins 2 and 3 function within the border cells, and Innexin 4 functions within the germline, to regulate microtubules. The microtubule-dependent border cell-oocyte interaction is essential to brace the cells against external morphogenetic forces. Thus, we establish an experimental model and use genetic, thermogenetic, and live imaging approaches to uncover the contributions of Innexins and microtubules to a cell biological process important in development and cancer, which we call neolamination in parallel to the established term delamination.