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Research Interest:
The basic mechanisms of cell differentiation are similar among different species; mutations of evolutionary conserved genes that are hierarchically arranged in signaling pathways often lead to similar abnormalities in various vertebrates, from zebrafish to human. Stem cells are the early embryonic cells giving rise to clones of differentiated cells populating various tissues and organs of vertebrate embryo. Hence, information obtained through molecular analysis of cell differentiation in wild type zebrafish and its mutants might be helpful in understanding mechanisms of maintenance of stem cells as well as model some human hereditary diseases, where elements of evolutionary conserved mechanism may be impaired. To date, Dr. Korzh discovered many genes involved in neural differentiation. Their role in specification of the cell fate during development needs to be analyzed. To this end the zebrafish embryos are manipulated by cell ablation, labeling and transplantation; gene activity is regulated in a whole embryo or in specific cells/groups of cells in vivo. Currently, his group is focused on monitoring neurodevelopment in vivo, obtaining mutations in genes that affect neural stem cells and/or mimicking effects of mutation. They developed novel research tools to reveal and modulate activity of developmental genes in neural stem cells. These include, firstly, an efficient method of insertional transgenesis using the green fluorescent protein (GFP)-tagged transposon that is used to reveal activity of regulatory elements (enhancers) that modulate gene activity in tissue-specific manner. The transgenic zebrafish presents very useful research tool that allows continuous analysis of gene regulation in the living embryo during the whole period of development and maturation. Secondly, a novel technique of massive electroporation of DNA into a neural tube of zebrafish embryo solved a long standing problem of analysis of gene function during late development and, in particular, late neurodevelopment of zebrafish. In result, the gene function during formation and function of the neural stem cells can be better understood. For example, we discovered and described several genes encoding basic helix-loop-helix proneural proteins (Neurogenin1, Zath3/Neurod4, etc) and other factors expressed in neural stem cells of zebrafish, including Pax6/zf-pax-a. Currently, we actively pursue functional analysis of some of these genes. In continuation of these efforts we recently cloned several other genes known to function in neural stem cells, including members of Sox, GFAP and integrin gene families (our unpublished results). The enhancer-trap (ET) transgenic zebrafish lines are currently used in this laboratory to study in vivo molecular mechanisms of neural stem cells role during neurodevelopment.
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