Chen, D. et al. Cell Rep. 21, 559–569 (2017).

Cells migrate throughout tissues as a normal part of development and maintenance. Most methods for tracking cell migration involve live imaging, which has provided crucial mechanistic understanding but can have unwanted effects on the physiology of an organism. To bypass some of these limitations, Chen et al. have developed a tool called M-TRAIL (matrix-labeling technique for real-time and inferred location) for tracing migration histories in fixed tissues. In M-TRAIL, migrating cells are engineered to express fluorescent-protein-tagged components of the basement membrane, which are secreted and deposited into the extracellular matrix as the cell migrates, and this marks the path of migration in a way that allows quantification of migratory dynamics. M-TRAIL was demonstrated in the Drosophila egg chamber, where the team was able to validate the hypothesis that tissue rotation is required for elongation.