Production of Transgenic Olive Flounder (Paralichthys olivaceus) I. In vivo Gene Transfer in Olive Flounder by Direct Intramuscular Injection

The carp β-actin regulatory sequences and RSV/LTR promoter were tested whether they are functional to express linked structure gene (chloramphenicol acetyltransferase, CAT) in olive flounder (Paralichthys olivaceus) by determining the patterns of gene expression following intramuscular in vivo direct injection. The injection experiments with various concentrations of both pRSVCAT and pFV4CAT clearly revealed the effectiveness of DNA dosage on expression of CAT. The increase of CAT activity was linear in both plasmids, and maximal CAT activity was obtained with 100 ㎍ of pFV4CAT injection. The amounts of CAT expression with pFV4CAT-injected fish were higher than those with pRSVCAT-injected fish. CAT activity was readily detectable as early as one day after injection, slightly increased at day 2, and declined over time. Most amount of DNA intramuscularly injected into olive flounder muscles persisted extrachromosomally without showing any integrated or replicated form in vivo.