GATA-1 EXPRESSION PATTERN CAN BE RECAPITULATED IN LIVING TRANSGENIC ZEBRAFISH USING GFP REPORTER GENE

In this study, DNA constructs containing the putative zebrafish promot er sequences of GATA-1, an erythroid-specific transcription factor, an d the green fluorescent protein reporter gene, were microinjected into single-cell zebrafish embryos, Erythroid-specific activity of the GAT A1 promoter was observed in living embryos during early development, F luorescent circulating blood cells were detected in microinjected embr yos 24 hours after fertilization and were still present in 2-month-old fish, Germline transgenic fish obtained from the injected founders co ntinued to express green fluorescent protein in erythroid cells in the Fl and Fz generations, The green fluorescent protein expression patte rns in transgenic fish were consistent with the pattern of GATA-1 mRNA expression detected by RNA in situ hybridization, These transgenic fi sh have allowed us to isolate, by fluorescence-activated cell sorting, the earliest erythroid progenitor cells from developing embryos for i n vitro studies, By generating transgenic fish using constructs contai ning other zebrafish promoters and green fluorescent protein reporter gene, it should be possible to visualize the origin and migration of a ny lineage-specific progenitor cells in a living embryo.