Moygenic and angiogenic stem cells in the teleost myotome

Our understanding of the developmental patterns and causal mechanisms which allow `stem cells` to differentiate into any of a wide spectrum of tissue types is a central issue in modern developmental biology. In teleost fish, results of recent research, often on zebrafish, provide a useful but limited picture of the origins of myogenic and angiogenic stem cells and development of these into muscle fibres and blood vessels, respectively. From our own previous FWF-funded projects, we have been able to considerably expand upon the zebrafish model and extend its overall generality in the direction muscle fibre development. However, equivalent new research involving vasculogenesis remains lacking. The proposed research will examine the formation of muscle cells and the associated growth of the necessary blood capillaries in selected species of teleost fish from temperate freshwaters. The work will shed new light upon the dynamics and interactions between fish muscle fibres and muscle capillaries during their early development, with an aim to make important advances in our knowledge of the roles of stem cells, particularly their repertoir of differen-tiation, in the developmental biology of fish. Specifically, the aims of the work are to address questions of (a) patterns of vascular development and their correlation with patterns of myogenesis in the embryo, (b) microvascular development after the onset of larval (`mosaic`) muscle hyperplasia, and (c) the influence of environmental temperature on muscle capillary growth. The methods to be used are all standard procedures in our laboratory and include in situ hybridization, immunocytochemistry, histochemistry, light- and electron microscopy, morphometry and stereology. It is expected that the results will be of major significance to stem cell research in fish and will be of use in both pure and applied developmental biology and in zoological research of teleosts and other vertebrates.