title: Characterization and mutational analysis of omega-class GST (GSTO1) from Apis cerana cerana, a gene involved in response to oxidative stress.
abstract: The Omega-class of GSTs (GSTOs) is a class of cytosolic GSTs that have specific structural and functional characteristics that differ from those of other GST groups. In this study, we demonstrated the involvement of the GSTO1 gene from A. cerana cerana in the oxidative stress response and further investigated the effects of three cysteine residues of GSTO1 protein on this response. Real-time quantitative PCR (qPCR) showed that AccGSTO1 was highly expressed in larvae and foragers, primarily in the midgut, epidermis, and flight muscles. The AccGSTO1 mRNA was significantly induced by cold and heat at 1 h and 3 h. The TBA (2-Thiobarbituric acid) method indicated that cold or heat resulted in MDA accumulation, but silencing of AccGSTO1 by RNAi in honeybees increased the concentration of MDA. RNAi also increased the temperature sensitivity of honeybees and markedly reduced their survival. Disc diffusion assay indicated that overexpression of AccGSTO1 in E. coli caused the resistance to long-term oxidative stress. Furthermore, AccGSTO1 was active in an in vitro DNA protection assay. Mutations in Cys-28, Cys-70, and Cys-124 affected the catalytic activity and antioxidant activity of AccGSTO1. The predicted three-dimensional structure of AccGSTO1 was also influenced by the replacement of these cysteine residues. These findings suggest that AccGSTO1 plays a protective role in the response to oxidative stress.
authors.affiliation: College of Life Sciences, Shandong Agricultural University, Taian, Shandong, P. R. China.
authors.forename: Fei
authors.initials: F
authors.lastname: Meng
authors.affiliation: College of Life Sciences, Shandong Agricultural University, Taian, Shandong, P. R. China.
authors.forename: Yuanying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: College of Animal Science and Technology, Shandong Agricultural University, Taian, Shandong, P. R. China.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.affiliation: College of Life Sciences, Shandong Agricultural University, Taian, Shandong, P. R. China.
authors.forename: Xingqi
authors.initials: X
authors.lastname: Guo
authors.affiliation: College of Animal Science and Technology, Shandong Agricultural University, Taian, Shandong, P. R. China.
authors.forename: Baohua
authors.initials: B
authors.lastname: Xu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000378:metabolism; D001516:Bees / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D004249:DNA Damage; D004252:DNA Mutational Analysis; D005786:Gene Expression Regulation; D019476:Insect Proteins / Q000737:chemistry / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism*; D008315:Malondialdehyde / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D018384:Oxidative Stress; D011487:Protein Conformation; D034622:RNA Interference; D013696:Temperature
chemical_list: D000975:Antioxidants; D019476:Insect Proteins; D008315:Malondialdehyde