| Project Detail |
Behaviour of the actin cortex during egg fertilisation
Little is known about the molecular and biophysical mechanisms that occur at the moment of gamete interaction, specifically how the elasticity of the actin cortex is regulated during egg fertilisation. Previous microscopy techniques lacked adequate spatiotemporal resolution to capture this dynamic process that occurs instantaneously. Funded by the Marie Sklodowska-Curie Actions programme, the Egg-Cortex project aims to identify the molecular and mechanical properties of the egg actomyosin cortex. For this purpose, it will extract eggs from zebrafish that can be stimulated in the absence of sperm to study the structural and behavioural patterns of the cortical matrix using state of-the-art single-molecule imaging and optical tweezers.
The fusion of two specialized gametes represents the starting point of life in sexually reproductive organisms. Despite this fundamental role in the creation of life, the molecular and biophysical mechanisms underlying this process remain largely elusive. It is evident that the dynamic modulation of the egg actomyosin cortex plays a central role during different steps of fertilization including cortical granule exocytosis, Ca2+ signaling and sperm uptake. How this high plasticity of the actin cortex is regulated during fertilization has not been studied in detail. In the past, research of this dynamic process has been limited by live-cell microscopy techniques lacking the needed spatiotemporal resolution. Gamete interaction is not only a very fast process; in mammals, it also occurs synchronously with gamete activation. To overcome these limitations, we propose utilizing eggs isolated from zebrafish that can be activated independently of interaction with sperm. Specifically, we will comparatively characterize the dynamic egg actomyosin cortex properties during fertilization using advanced single-molecule imaging techniques and biophysical tools like optical tweezers. We will specifically address whether the egg actin cortex has mechanosensitive properties that might facilitate gamete fusion, as has been shown for other cell-cell fusion events. It is our goal to identify the basic molecular and biophysical mechanisms underlying fertilization, and the comprehensive quantitative study of actin structures within the egg cortex will establish an essential step in addressing this question. |
