Analysis of heterologous and homologous promoters and enhancers in vitro and in vivo by gene transfer into Japanese medaka (Oryzias latipes) Xiphophorus.

Efficient expression systems are required for analysis of gene regulation and function in teleost fish. To develop such systems, a number of inducible or constitutive promoter and enhancer sequences of fish or higher vertebrate origin were tested for activity in a variety of fish cell lines and in embryos of the Japanese medaka fish (Oryzias latipes) and Xiphophorus. The activity of the different promoter-enhancer combinations were quantitated. Considerable differences were found for some constructs if tested in vitro or in vivo. Fro the data obtained, a set of expression vectors for basic research as well as for aquaculture purposes were established.