Conservation of a glutathione S-transferase in marine and freshwater fish

We have previously reported the isolation and cloning of glutathione S-transferase (GST) cDNAs from two marine fish, English sole (Pleuronectes vetulus) and starry flounder (Platichthys stellatus), that exhibited >95% identity to plaice (Pleuronectes platessa) GST-A Aquatic Toxicol., 44, 171–182]. In the present study, we have used reverse transcription–polymerase chain reaction (RT–PCR) analysis to isolate a 471 nucleotide GST-like cDNA from largemouth bass (Micropterus salmoides) liver. Sequence identity of the largemouth bass partial cDNA to plaice GST-A was approximately 90%. Northern blotting analysis using the partial GST cDNA from English sole as a probe detected a single band of approximately 1 kb in English sole liver and a slightly larger GST-like band that was highly expressed in largemouth bass liver. In addition, a faint band of similar size was recognized in brown bullhead (Ameriurus nebulosus) liver, but not in channel catfish (Ictalurus punctatus) liver. In conclusion, we have extended our studies of GST expression in flatfish and have isolated an additional GST-A-like cDNA from a largemouth bass. Conservation of a GST-A like cDNA among certain marine flatfish and freshwater species suggests an important function for this gene.