Moving cells can sense and respond to physical features of the microenvironment; however, in vivo, the significance of tissue topography is mostly unknown. Here, we used Drosophila border cells, an established model for in vivo cell migration, to study how chemical and physical information influences path selection. Although chemical cues were thought to be sufficient, live imaging, genetics, modeling, and simulations show that microtopography is also important.

Apoptosis is an ancient and evolutionarily conserved cell suicide program. During apoptosis, executioner caspase enzyme activation has been considered a point of no return. However, emerging evidence suggests that some cells can survive caspase activation following exposure to apoptosis-inducing stresses, raising questions as to the physiological significance and underlying molecular mechanisms of this unexpected phenomenon. Here, we show that, following severe tissue injury, Drosophila wing disc cells that survive executioner caspase activation contribute to tissue regeneration.

Dai, Guo et al, Science, in press

Cell motility is essential for embryonic development, adult homeostasis, tumor cell

dissemination, and immunity. Migrating cells navigate physical features of their

microenvironment, however the in vivo significance of tissue topography for pathfinding is

mostly unknown. Dai, Guo et al. use Drosophila border cells to study path selection in vivo.

Experiments, mathematical modeling and simulations show that tissue microtopography

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.