Tuning cell division machinery in oocytes using light

The process of cell division relies on the coordination of chemical and mechanical signals in response to cell cycle cues. During early developmental processes in starfish egg cells, actomyosin contractility is patterned by Cdk1 gradients through the activation of Rho-GTP pathway, and organizes the large-scale shape deformation that can be observed in either asymmetric (meiosis) or symmetric (mitosis) divisions. To investigate the role of geometry, mechanics and biochemistry, we decouple the Rho-actomyosin pathway from pre-patterned cell cycle signals by engineering and delivering an optogenetic activator of Rho-GTP into starfish oocytes arrested at the prophase of meiosis I. Using the light activation of local Rho-GTP combined with global shape perturbations, we can induce large-scale mechanical deformations seen during symmetric and asymmetric cell division. Our results can shed light on mechanisms of mechanochemical patterns and provide a blueprint for designing programmable active mechanochemical materials.