The wide range of muscle morphologies found across the animal kingdom enables intricate movements essential for various behaviors, such as feeding, mating, or even tasks like writing a summary for a seminar. Many animals rely on appendages for their locomotion, which feature multifiber muscles with diverse morphologies enabling unique functions. Despite extensive study and understanding of the general program of muscle development (how myoblasts produce muscles), the specific program controlling the diversity of muscle morphologies in multifiber muscles (how myoblasts produce unique muscles) remains unknown. Using Drosophila leg muscles as a model system, we have revealed that myoblasts, in parallel with the general program of myogenesis, express distinct transcriptional programs that specify muscle morphologies. Moreover, we found that the spatiotemporal progression of these programs is regulated by morphogenes secreted by the underlying epithelium. To achieve these conclusions, we used unique genetic and computational tools combined with single-cell sequencing. Our findings provide a framework for the developmental and evolutionary origins of appendicular muscles and may help explain the selective vulnerability of specific muscles in muscular dystrophies.

I would also give a couple of words of a pipeline of 3D Spatial transcriptomic (3D MERFISH) we have developed in the context of The Equipex+, Spatial Cell ID.

Jonathan Enriquez is invited by Pascal Maire.