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

Abstract

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.