Probing tissue interaction with laser-based cauterization in the early developing Drosophila embryo.

Tissue morphogenesis is governed by mechanical forces generated by cell cytoskeletal networks. It has been shown that subcellular forces are responsible for cell shape changes. Nevertheless cells in a developing organism do not act in isolation: cells contact and adhere one another, and forces are transmitted from cell-to-cell throughout tissues. Understanding how forces are integrated at the tissue level and finally at the full animal scale is nowadays a major challenge that will allow shedding new light on how embryo morphogenesis takes place. In this chapter, I present a new laser-based technique to probe tissue coupling in a living Drosophila embryo. Such technique allows generating mechanical fix boundaries that can eventually impair or modulate cell flows and tissue displacements to probe tissue interaction.