title: A Mu-class glutathione S-transferase (GSTM) from the rock shell Thais clavigera.
abstract: The rock shell (Thais clavigera) has attracted interest due to high frequency of imposex induced by endocrine disrupting chemicals (EDCs) in its natural populations. Oxidative stress is one of the mechanisms of action of EDCs. Glutathione S-transferases (GSTs) play an important role in antioxidant defense protecting the cells from oxidative stress. So far, there is no information on antioxidant defense or detoxification genes from T. clavigera. We cloned the full length cDNA sequence for a Mu-class of GST gene from T. clavigera (Tc-GSTM) and purified recombinant Tc-GSTM protein by bacterial expression. The deduced amino acid sequence of Tc-GSTM exhibited 45 to 66% identity with other Mu-class GSTs. Real-time RT-PCR analysis showed highest expression of Tc-GSTM in gill, while reproductive organs showed low expression. The biochemical characteristics of purified recombinant Tc-GSTM were typical, and thus Tc-GSTM showed highest specific activity for the universal GST substrate, 1-chloro-2,4-dinitrobenzene (CDNB). After exposure to prooxidant H(2)O(2), transformed Escherichia coli containing Tc-GSTM showed higher survival rate compared to control bacteria without expressed Tc-GSTM. The present study reveals a conserved antioxidant role for GSTM in rock shells, and the tissue-specific differences in Tc-GSTM transcripts would partly reflect vulnerability of reproductive organs to chemically induced oxidative stress.
authors.affiliation: Department of Molecular and Environmental Bioscience, Graduate School, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Jae-Sung
authors.initials: JS
authors.lastname: Rhee
authors.forename: Sheikh
authors.initials: S
authors.lastname: Raisuddin
authors.forename: Dae-Sik
authors.initials: DS
authors.lastname: Hwang
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Horiguchi
authors.forename: Hyeon-Seo
authors.initials: HS
authors.lastname: Cho
authors.forename: Jae-Seong
authors.initials: JS
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D049851:Gastropoda / Q000737:chemistry / Q000235:genetics; D005982:Glutathione Transferase / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D014018:Tissue Distribution
chemical_list: D000975:Antioxidants; D005982:Glutathione Transferase