title: Molecular Cloning and mRNA Expression of Heat Shock Protein Genes and Their Response to Cadmium Stress in the Grasshopper Oxya chinensis.
abstract: Heat shock proteins (Hsps) are highly conserved molecular chaperones that are synthesized in response to stress. In this study, we cloned the full-length sequences of the Grp78 (glucose-regulated protein 78), Hsp70, Hsp90, and Hsp40 genes from the Chinese rice grasshopper Oxya chinensis. The full-length cDNA sequences of OcGrp78, OcHsp70, OcHsp90, and OcHsp40 contain open reading frames of 1947, 1920, 2172, and 1042 bp that encode proteins of 649, 640, 724, and 347 amino acids, respectively. Fluorescent real-time quantitative PCR (RT-qPCR) was performed to quantify the relative transcript levels of these Hsp genes in different tissues and developmental stages. The mRNAs encoding these four Hsp genes were present at all developmental stages and in all tissues examined but were expressed at varying levels. Additionally, we investigated the mRNA expression profiles of these four Hsps in O. chinensis subjected to Cadmium (Cd) stress. OcGrp78, OcHsp70, OcHsp90, and OcHsp40 mRNA expression was induced under acute Cd stress; the levels reached a maximum within a short time (6 h), were reduced significantly at 12 h, and were lowered to or below control levels by 48 h. Regarding induction efficiency, OcHsp70 was the most sensitive gene to acute Cd stress. Chronic Cd exposure showed that dietary Cd treatment induced increased OcGrp78, OcHsp90, and OcHsp40 expression. However, dietary Cd induced a significant reduction of OcHsp70 expression. In the period tested, no significant difference in the mortality of the grasshoppers was observed. Our results suggest that these four Hsps genes, especially OcHsp70, are sensitive to acute Cd stress and could be used as molecular markers for toxicology studies. However, our results also indicate that OcHsp70 is not suitable for use as a molecular marker of chronic Cd contamination.
authors.affiliation: Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi, China; Biology Department, Taiyuan Normal University, Taiyuan, Shanxi, China.
authors.forename: Yuping
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi, China.
authors.forename: Yaoming
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi, China.
authors.forename: Jianzhen
authors.initials: J
authors.lastname: Zhang
authors.affiliation: College of Life Science, Shanxi University, Taiyuan, Shanxi, China.
authors.forename: Yaping
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi, China.
authors.forename: Enbo
authors.initials: E
authors.lastname: Ma
mesh_terms: D000818:Animals; D002104:Cadmium / Q000633:toxicity*; D003001:Cloning, Molecular; D000091342:Endoplasmic Reticulum Chaperone BiP; D005260:Female; D005786:Gene Expression Regulation; D006110:Grasshoppers / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D050956:HSP40 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D007814:Larva / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D008297:Male; D016366:Open Reading Frames; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013312:Stress, Physiological; D015053:Zygote / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism
chemical_list: D000091342:Endoplasmic Reticulum Chaperone BiP; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D019476:Insect Proteins; D012333:RNA, Messenger; D002104:Cadmium