The green-fluorescent protein (GFP) of the jellyfish Aequorea victoria has recently been used as a universal reporter in a broad range of heterologous living cells and organisms. Fertilized eggs of the Carp (Cyprinus carpio) in the
period of blastodisc formation and up to the fourth division of the cleavage were injected with two plasmids expressing the natural jellyfish GFP and synthetic engineered jellyfish (sGFP) using Microinjection method. Reverse transcription
PCR products, cloning, sequencing, were analysed. Using universal transcription and translation enhancers with strong promoters, has been showed that GFP signals are detectable in transient expression systems of fish. The engineered
GFP gene sequence gave higher GFP expression in fish than the natural jellyfish GFP sequence. This new tool can be used for studies of gene regulation, signal transduction, development and cell biology in animals and plants.