Generation of living color transgenic zebrafish

Summary

Use of green fluorescent protein (gfp) as a reporter gene is a powerful approach for the investigation of tissue-specific gene expression and cellular localization of proteins because the fluorescence of its protein product can be conveniently detected in living cells without supplementing a substrate. The approach is particularly useful in zebrafish because of the transparency and external development of their embryos. In the past few years, using several zebrafish tissue-specific promoters, we have developed several stable lines of gfp transgenic zebrafish that display green fluorescence in different tissues; these include five transgenic lines under an epidermis-specific keratin8 (krt8) promoter, two transgenic lines under a fast skeletal muscle-specific promoter from the myosin light polypeptide 2 (mylz2) gene, and five transgenic lines under an elastaseA (elaA) promoter that is specifically expressed in pancreatic exocrine cells. In all cases, transgenic GFP is faithfully expressed according to the specificity of the promoters used. These gfp transgenic lines are useful for recapitulation of a gene expression program, investigation of tissue and organ development, cell sorting for in vitro cell culture, and construction of cell type-specific cDNA library. Recently, by using two tissue-specific promoters linked to two different reporter genes, gfp and rfp (red fluorescent protein), we have generated two-color transgenic zebrafish that express GFP in skin epidermis and RFP in fast skeletal muscle. Currently, we are also developing gfp transgenic fish for biomonitoring using selected inducible gene promoters that can respond to heavy metals and estrogenic compounds. Thus, generation of living color transgenic zebrafish will have important applications in biotechnology as well as in developmental biology.