Centrioles are the core structural component of centrosomal microtubule organising centres and are essential for cell division, differentiation, and maturation during mammalian embryogenesis. Delta tubulin has been implicated in the stability of centriole triplet microtubules in unicellular species (1) and is required for mammalian spermatogenesis (2), but its in vivo role during early embryogenesis has remained unknown. Herein, we leveraged the process of de novo centriole formation in mouse embryos to examine the function of delta tubulin at centrosomal and non-centrosomal microtubule organising centres.
Through creation of a whole-body knockout mouse model of its gene, Tubd1, we reveal that delta tubulin gradually localises to the developing mouse centrosome at blastocyst stages (p = 0.0028) and is essential for early embryogenesis. Loss of delta tubulin function leads to developmental arrest and embryonic lethality at mid-gestation and importantly, the function of other tubulin proteins (alpha, beta, gamma, epsilon) cannot compensate for its absence. We identify a 91.4% reduction in centrosome number within delta tubulin knockout embryos (p < 0.0001) and a complete absence of cilia. Moreover, we show that delta tubulin is needed for the progression and completion of centrosome-dependent mitosis during post-implantation development. Lastly, we reveal that delta tubulin’s function is restricted to the centrosome and that non-centrosomal microtubule structures are not perturbed in its absence. This work provides a necessary insight into delta tubulin’s cellular function, enhances the understanding of how abnormalities within the microtubule cytoskeleton contribute to defects in early embryogenesis and may inform tubulinopathies and ciliopathies associated with various disease manifestations.