Dual genetic lineage tracing reveals functional neuromesodermal progenitors
In the past decades, the paradigm of three germ layers formed by gastrulation has been modified by data suggesting an existence of neuromesodermal progenitors (NMPs) that arise during gastrulation and contribute to both spinal cord and adjacent paraxial mesoderm1-5. However, there lacks direct genetic lineage tracing evidence and functional assessment of NMPs in vivo. Here, we develop a dual recombinases-mediated genetic system to specifically trace and genetically ablate Brachyury+Sox2+ NMPs. Genetic lineage tracing results and single-cell RNA sequencing analysis show that NMPs contain three distinct uni-potent and bi-potent progenitor populations for progressive differentiation into neural and mesodermal fates. Genetic ablation of NMPs by diphtheria toxin reveals a critical role of NMPs in tail formation. This study provides in vivo genetic evidence for heterogeneity of NMPs in their cell fate determination and their functional role in developing embryos. Overall design: caudal tissue of C57BL/6J mice were isolated and analyzed using scRNAseq.