Gene expression pattern (GEP) dynamics during development provide insight into morphogenesis, but they can be challenging to image in real time. For example, mouse embryos develop in utero, meaning that GEP dynamics can only be accessed by imaging fixed embryos at discrete developmental stages. This technique provides mere snapshots of the process. Here, Laura Aviñó and colleagues present a pipeline for reconstructing gene expression patterns in the developing mouse limb bud. In previous work, they had represented the developing limb bud as a mesh of triangles, where the vertices of the mesh adjust as the limb bud grows and changes shape. The authors leverage this approach here, taking existing images of Sox9 (a skeletal progenitor cell marker) expression in the limb bud, staging them and morphing them onto the mesh that corresponds to the assigned developmental stage. They develop an interpolation method to infer Sox9 GEPs in the missing timepoints, thus creating a continuous timelapse from discrete static images. The authors go on to demonstrate that this technique can be applied to other genes in the limb bud and to genes in the mouse neural tube. Overall, this new pipeline offers insight into GEP dynamics that could be used to inform future modelling efforts.
