Inheritance of P element and reporter gene sequences in zebrafish

We have established 15 separate lines of zebrafish transgenic for two plasmid DNAs containing Drosophila P element sequences and either the reporter genes chloramphenicol acetyltransferase (CAT), neomycin phosphotransferase (NPT), and beta-galactosidase (BGAL) or the reporter gene hygromycin phosphotransferase (HPT). Transient expression of CAT, but not NPT or BGAL, could be measured in the G0 (microinjected) generation, while expression in subsequent generations was below the limit of detection for CAT and NPT. All 15 lines contain stable low copy number integrations of between one and five transgene copies per cell with characteristic Southern blot "junction fragments" and have shown Mendelian inheritance after the G1 generation. The transgenes in 13 of 15 of the lines were originally inherited by about 10% or less of the G1 fish, suggesting a mosaic integration into the germline. Of 14 tested lines, none is associated with an embryonic recessive lethal phenotype as scored in the G3 generation.