title: Expression profiles of glutathione S-transferase genes in larval midgut of Bombyx mori exposed to insect hormones.
abstract: Glutathione S-transferases (GSTs) are believed to play a role in the detoxification of xenobiotics, resistance to insect viruses and pesticides, intracellular transport, biosynthesis of hormones and protection against oxidative stress. In this study, we used quantitative real time RT-PCR to examine expression profiles of the silkworm Bombyx mori GST-Sigma (BmGSTS2) and GST-Delta (BmGSTD2) genes in the larval midgut of the silkworm after exposure to 2-hydroxyecdysone (20E) and juvenile hormone analog (JHA). In concentration-course study, 20E at higher concentrations (1.0 and 2.0 μg/μl) caused significant upregulation of BmGSTD2, and all concentrations (0.5-2.0 μg/μl) of 20E caused significant upregulation of BmGSTS2. However, JHA in all concentrations downregulated the expression of BmGSTD2 and BmGSTS2. When exposed to either 20E (2.0 μg/μl) or JHA (2.0 μg/μl) on the third day of the fifth instar, the silkworm had higher BmGSTD2 at later time points: 15, 18, and 24 h for 20E and 24 h for JHA. BmGSTS2 expression was downregulated within 24 h after exposure to JHA and showed a time-dependent response after exposure to 20E. We also did a stage-dependent study, in which JHA downregulated BmGSTD2 expression and upregulated BmGSTS2 expression significantly at both day 1 and day 3 of the fifth instar. 20E upregulated the expression of BmGSTD2 and BmGSTS2 at the two stages. These findings imply that hormones have an important role in the regulation of basal GST expression. However, further validation and field trials should be carried out on the regulatory elements relevant to BmGSTD2 and BmGSTS2 gene expression.
authors.affiliation: School of Biology and Environmental Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212018, China.
authors.forename: Feng-Ming
authors.initials: FM
authors.lastname: Zou
authors.forename: De-Shuai
authors.initials: DS
authors.lastname: Lou
authors.forename: Ya-Hong
authors.initials: YH
authors.lastname: Zhu
authors.forename: Sheng-Peng
authors.initials: SP
authors.lastname: Wang
authors.forename: Byung-Rae
authors.initials: BR
authors.lastname: Jin
authors.forename: Zhong-Zheng
authors.initials: ZZ
authors.lastname: Gui
mesh_terms: D000818:Animals; D012831:Bombyx / Q000187:drug effects / Q000235:genetics*; D019295:Computational Biology; D004064:Digestive System / Q000187:drug effects* / Q000201:enzymology*; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D017344:Genes, Insect / Q000235:genetics*; D005982:Glutathione Transferase / Q000235:genetics*; D007301:Insect Hormones / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects / Q000235:genetics; D008969:Molecular Sequence Data; D009691:Nucleic Acid Denaturation / Q000187:drug effects; D011401:Promoter Regions, Genetic / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
chemical_list: D007301:Insect Hormones; D005982:Glutathione Transferase