Green fluorescent protein (GFP) as a tracer dye for cell movements in developing zebrafish embryos

Abstract

Fluorescent dyes have been extremely useful in determining cell lineages in the developing zebrafish embryo. For example, injection of FITC-dextran into blastomeres has allowed the determination of a tissue fate map at late blastula and a description of cell movements during gastrulation. Here we describe the use of green fluorescent protein (GFP) as a tracer dye for cell movements in developing early zebrafish(Danio rerio)embryos. Since GFP was purified and cloned from the jellyfishAequorea victoria,it has attracted great attention from biologists as an in vivo tracer and a reporter gene. The protein requires no cofactors or substrates for its fluorescence. This property allows one to inject GFP DNA constructs or in vitro synthesized GFP mRNA into individual cells which can then be expected to continuously synthesize the protein, thus obviating the dilution and bleaching effects often observed when fixed amounts of fluorescent tracer dyes are injected into dividing cells.