Mitotic waves

01 Jan 2024 - Irene

Post-fertilisation, a single-celled oocyte becomes an early embryo in a process termed “cleavage”, consisting of several rounds of rapid mitotic cell divisions, partitioning the large volume of the oocyte into thousands of somatic-sized cells and specifying the blueprint for subsequent embryo developments. It has also been observed that the timings of the cell divisions exhibit travelling wave like behaviours, known as mitotic waves. The waves emanate from the animal pole, the top of the embryo when oriented with respect to gravity, and travels towards the vegetal pole at the bottom. There is evidence suggesting that the local cell division cycles have different natural frequencies depending on their positions along the animal-vegetal axis. Remarkably, preliminary data showed that the mitotic waves persist without cell membranes, albeit with subtly different characteristics: the wavefronts are much smoother and more regular in cytokinesis-defective embryos. We thus hypothesize that, the absence of cell membranes enhances the coupling between neighbouring cells. This also constitutes an ideal model system to study the interaction between temporal oscillations and spatial cytoplasmic self-organisation, introducing a novel class of active matter model with a wide range of applications in other oscillatory biological systems such as somitogenesis and seminiferous cycles.

This project is in collaboration with Dr. Nikhil Mishra and Prof. CP Heisenberg at ISTA.