Cytoskeleton dynamics in embryogenesis
Embryogenesis comprises of serial, and on occasion simultaneous, occurrence of highly coordinated and regulated processes that lead to the formation of an organism. These processes are fairly conserved in all animal embryos. During embryogenesis, morphogenetic changes take place to bring about the formation of tissues from an initial mass of cells. Morphogenesis relies on individual and collective cell changes in shape, neighbourhood or identity to drive the generation and folding of individual tissues and organs to allow their functionality. Extensive research has focused on the mechanisms that orchestrate morphogenesis, yet much remains unexplored. One of the areas that remains poorly characterized is how the individual cellular machineries
contribute to the overall tissue formation, in particular, how the cell’s skeleton – the cytoskeleton - is spatio-temporally regulated in terms of architecture and dynamics. In contrary to our perception of the human skeleton, tough and rigid, the skeleton of a cell can assume diverse and complex structures and reorganize within seconds, allowing a given cell to accurately respond to changes in its environment and interior. The changes can be chemical like signalling pathways or can be physical where the rigidity of the outside environment or forces generated by the surrounding cells, which dictate changes like direction of cell migration, shape change and formation of new junctions with new neighbours etc. Not surprisingly, the cytoskeleton is crucial in the formation of stable cell-cell and cell-matrix junctions and also transient lamellipodia and filopodia for cellular motility. The key cytoskeletal components – actin, microtubules and intermediate filaments - form dynamic networks which are crucial for successful execution of key events in morphogenesis, like cell intercalation, rearrangements, migration, adhesion to neighbouring cells and the matrix. The ambiguous flexibility and strength exhibited by the cytoskeleton places has increasingly awakened curiosity.
The Caenorhabditis elegans nematode embryo is an excellent model to explore the dynamics of the cytoskeleton. Not only the main processes that define embryogenesis are conserved, but also the molecules that enable them. The transparent embryo makes it an excellent system for microscopy, as fluorescently tagged molecules can be easily imaged. Its invariant lineage helps us to track individual cells during embryogenesis very easily. In addition, genetic tools like Crispr-Cas9 is feasible which allows us to manipulate our genes of interest. Equipped with these tools and this simple yet powerful model system, we intend to shed light on mechanisms that govern cytoskeletal architecture and dynamics in the context of tissue morphogenesis.