View Program - 63rd Annual Drosophila Research Conference

Collective cell migration is paramount throughout a multicellular organism’s life from embryogenesis to adult tissue maintenance. Many cell migration studies are conducted in vitro, but to understand the full complexity of the living tissue environment, more in vivo studies are required. Using the border cells, which navigate as a cluster through the 3-D terrain of the Drosophila egg chamber during oogenesis, we can investigate the impact of physical architecture on collective cell migration and migration-related signaling in vivo. We observe small, acellular gaps at cell-cell junctures along the border cell migration route and hypothesize that these architectural features directly affect the migration behaviors of the border cells, in part by altering local distributions of secreted chemical attractants (chemoattractants). In silico, we have demonstrated that these gaps can affect the distribution of the morphogen that specifies border cell fate, as well as the distribution of secreted chemoattractants. Using staining and imaging techniques, we characterized the geometry and distribution of these gaps in fixed tissue and observed changes in border cell behavior at cell-cell junctures where gaps are observed in live tissue. Furthermore, flooding these gaps with above-endogenous levels of chemoattractant delayed border cell migration, and thus we are considering the effect of receptor dynamics on cluster migration. Additionally, we are using two complementary methods to reveal the chemoattractant gradient and evaluate the influence of the egg chamber’s terrain on signal distribution and consequently, border cell migration. First, by inducing extra border cells throughout the egg chamber and examining their speed and persistence, we infer the positions of local hotspots of concentrated chemoattractant. And second, by tagging chemoattractants to visualize them, we can examine signal distribution in real-time. This data will further inform and allow us to refine our in silico models on how border cells might respond to the chemoattractant gradient. Our studies emphasize the importance of considering physical features of the tissue architecture when examining collective migration and migration-relevant signaling in vivo.

Evaluating the Effect of Architectural Features on Border Cell Migration in Drosophila