Cadmium-induced heme oxygenase-1 gene expression is associated with the depletion of glutathione in the roots of Medicago sativa.
Following previous findings that cadmium (Cd) induces heme oxygenase-1 (HO1) gene expression in alfalfa seedling roots, we now show that the decreased glutathione (GSH) and ascorbic acid (AsA) contents, induction of HO-1 gene expression and its protein level by Cd was mimicked by a GSH depletor diethylmaleate (DEM). Meanwhile, above Cd- or DEM-induced decreased GSH content followed by HO-1 up-regulation could be strengthened or reversed differentially by the application of a selective inhibitor of GSH biosynthesis L: -buthionine-sulfoximine (BSO), or exogenous GSH and AsA, respectively. The antioxidative behavior of HO-1 induction was further confirmed by histochemical staining for the detection of loss of membrane integrity in a short period of treatment time. Additionally, the induction of HO-1 transcript was inhibited by the transcriptional inhibitor actinomycin D (ActD) or protein synthesis inhibitor cycloheximide (CX, especially). In contrast, the level of HO-2 transcript did not change upon various treatments. Together, above results suggested that Cd-induced up-regulation of HO-1 gene expression is associated with GSH depletion, which is at least existing transcriptional regulation level, thus leading to enhanced antioxidative capability transiently.
Cui
Weiti
W
College of Life Sciences, Cooperative Demonstration Laboratory of Centrifuge Technique, Nanjing Agricultural University, Nanjing 210095, People's Republic of China.
Fu
Guangqing
G
Wu
Honghong
H
Shen
Wenbiao
W
D002104:Cadmium / Q000494:pharmacology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D005978:Glutathione / Q000378:metabolism*; D051547:Heme Oxygenase-1 / Q000235:genetics* / Q000378:metabolism; D000455:Medicago sativa / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D018517:Plant Roots / Q000201:enzymology / Q000378:metabolism*; D016133:Polymerase Chain Reaction
D002104:Cadmium; D051547:Heme Oxygenase-1; D005978:Glutathione