Unsuccessful attempt at gene-editing by homologous recombination in the zebrafish germ line using the approach of...

We have investigated the practicality of implementing a strategy for site-specific editing by homologous recombination in zebrafish analogous to that developed by Rong and Golic (Rong and Golic in Genetics 157:1307-1312, 2001) in Drosophila melanogaster. We analysed approximately 7,300 offspring from 22 crosses and demonstrated successful excision of the gene editing construct but failed to detect either gene editing or the random integration of the intact editing construct subsequent to excision. The clustering of events in our data set demonstrates that the excision events are not occurring independently and emphasise that a promoter driving high level, tissue-specific transcription in meiotic cells is likely to be necessary if this general approach to site-specific editing by homologous recombination is to fulfil its potential.