Establishment of a Chinook salmon cell line with an inducible gene expression system.

We have isolated a stable recombinant cell line CHSE-TOF5 derived from the Chinook salmon (Oncorhynchus tshawytscha) embryo cells for use as an inducible expression system. The cells were transfected with the pTet-Off plasmid from the Tet On/Off Clontech system, carrying a G418 resistance gene. Several G418-resistant clones were subcultured and characterised by quantitative PCR (qPCR) and by transient transfection. The level of expression of transcriptional activator was measured by qPCR in a number of isolated clones, and transient transfection with a pTRE2-hyg-LUC plasmid was used to evaluate the inducibility of these clones. A clone was selected for its relative fast cell growth and good level of inducibility. This genetically engineered cell line is a valuable tool for the fish research community especially in research areas investigating the biological function of proteins from fish or fish pathogens.