Coordinated neural tube closure: The role of biomechanical properties in directing neuropore (360G-Wellcome-105379_Z_14_A)

Neural tube (NT) closure is a morphogenetic event of vertebrate development that results in severe birth defects (e.g. spina bifida) when disturbed. The key genes/pathways of neurulation have been studied extensively, but many aspects of the developmental mechanisms remain unclear. This project addresses two questions: (i) how is neurulation linked mechanistically with the process of axial elongation, which accompanies spinal closure in higher vertebrates, and (ii) how/where do tissue-level biomechanical forces arise that drive NT morphogenesis? Neuro-mesodermal progenitors (NMPs) generate both neuroepithelium and mesoderm during axial elongation, and will be fate-mapped in the NT of cultured mouse embryos. Single-cell labelling by photo-conversion of cells expressing the Dendra2 construct will reveal the timing of neural commitment in NMPs. Requirement for NMPs in NT closure will be assessed in embryos mutant for Grhl3, a gene expressed in NMPs and where loss- or gain-of-function causes spina bifida. Biomechanical forces in the closing NT will be detected by electroporating a FRET-based mechanosensor that reports stress in cytoskeleton-linked proteins (e.g. alpha-actinin). Embryo manipulations (e.g. closed NT incision) will be tested for effects on FRET-reporter activity to identify the origin of closure forces, while mutant embryos developing spina bifida will be assessed for altered force distribution.