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Embryogenesis: solving mysteries of cell movements
The genetic make up of an organism is set at the moment of conception; but expression of that genotype in the form of a unique body depends upon early events in embryogenesis. Recognising the pervasive importance of those early events, Professor Robert Saint and his colleagues from the School of Biology Molecular Genetics and Evolution group have been researching the initial stages of developmental morphology for many years, making some ground-breaking discoveries on the way.
In one project, they are concerned with the molecular processes and gene controls that drive cell migration within a newly forming embryo, and for technical reasons, use genetically defined populations of vinegar fly (Drosophila melanogaster) as a model system. Because these Drosophila genes have mammalian counterparts, their findings are relevant to vertebrates. They are also relevant to cell migrations associated with tumours that spread by ‘seeding' a host with migratory cells.
Early in embryogenesis, a two-dimensional surface layer of cells is transformed into a complex three-dimensional body plan. Formation of internal tissue layers typically involves a state transition and subsequent movement of cells. By skilful use of mutant Drosophila, several genes critical to that migratory process have been identified, but difficulties in visualising the internal tissue in living embryos has limited understanding of cellular behaviour during that process.
In response to these difficulties, the Molecular Genetics and Evolution group recently pioneered a new type of fluorescence microscopy that represents a major advance in the area of imaging developing embryos. In one case, they were able to image living cells in Drosophila embryos using a specially-synthesised variant (photo-activatable) of the widely-employed Green Fluorescent Protein (GFP). This work has broadened their understanding of cell migration in general.
