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Regulation of gamma-glutamate-cysteine ligase expression by oxidative stress in the mouse preimplantation embryo.
Toxicol Appl Pharmacol. 2000 Oct 15; 168(2):153-9.TA

Abstract

The present study examined expression of gamma-glutamate-cysteine ligase (GLCL; also known as gamma-glutamylcysteine synthetase), the rate-limiting enzyme for de novo synthesis of glutathione, in the preimplantation mouse embryo. Previous studies indicated that the cleavage stage embryo is unable to synthesize glutathione de novo. It is hypothesized that GLCL mRNA and protein are not normally expressed in the cleavage stage embryo, but either glutathione depletion or oxidation may induce their expression. In untreated embryos, RT-PCR and Western blotting revealed GLCL heavy subunit (GLCL-H) mRNA and protein only at the blastocyst stage of development. Furthermore, while diethyl maleate (DEM) exposure to deplete cellular glutathione did not induce expression of GLCL-H, exposure to tertiary-butyl hydroperoxide (tBH), an oxidizing agent, resulted in significant upregulation of GLCL-H expression in two-cell embryos. Neither treatment affected expression in blastocysts. Finally, HPLC analysis confirmed that tBH-treated embryos experienced oxidative stress, as indicated by an increase in the ratio of oxidized to reduced glutathione. This oxidative stress induced de novo glutathione synthesis in the cleavage stage embryo, as demonstrated by the subsequent recovery of reduced glutathione levels following DEM-induced depletion. In the absence of tBH treatment, however, cleavage stage embryos could not recover GSH after DEM-mediated depletion. This study demonstrates that the preimplantation embryo has the capacity to upregulate glutathione synthesis in response to oxidative stress but not GSH depletion. These results suggest that, while the preimplantation embryo is well adapted to dealing with oxidative stress, it may be poorly protected from GSH-depleting toxicants.

Authors+Show Affiliations

Department of Biological Sciences, University of Northern Colorado, Greeley, Colorado, 80639, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

11032771

Citation

Stover, S K., et al. "Regulation of Gamma-glutamate-cysteine Ligase Expression By Oxidative Stress in the Mouse Preimplantation Embryo." Toxicology and Applied Pharmacology, vol. 168, no. 2, 2000, pp. 153-9.
Stover SK, Gushansky GA, Salmen JJ, et al. Regulation of gamma-glutamate-cysteine ligase expression by oxidative stress in the mouse preimplantation embryo. Toxicol Appl Pharmacol. 2000;168(2):153-9.
Stover, S. K., Gushansky, G. A., Salmen, J. J., & Gardiner, C. S. (2000). Regulation of gamma-glutamate-cysteine ligase expression by oxidative stress in the mouse preimplantation embryo. Toxicology and Applied Pharmacology, 168(2), 153-9.
Stover SK, et al. Regulation of Gamma-glutamate-cysteine Ligase Expression By Oxidative Stress in the Mouse Preimplantation Embryo. Toxicol Appl Pharmacol. 2000 Oct 15;168(2):153-9. PubMed PMID: 11032771.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Regulation of gamma-glutamate-cysteine ligase expression by oxidative stress in the mouse preimplantation embryo. AU - Stover,S K, AU - Gushansky,G A, AU - Salmen,J J, AU - Gardiner,C S, PY - 2000/10/18/pubmed PY - 2001/2/28/medline PY - 2000/10/18/entrez SP - 153 EP - 9 JF - Toxicology and applied pharmacology JO - Toxicol. Appl. Pharmacol. VL - 168 IS - 2 N2 - The present study examined expression of gamma-glutamate-cysteine ligase (GLCL; also known as gamma-glutamylcysteine synthetase), the rate-limiting enzyme for de novo synthesis of glutathione, in the preimplantation mouse embryo. Previous studies indicated that the cleavage stage embryo is unable to synthesize glutathione de novo. It is hypothesized that GLCL mRNA and protein are not normally expressed in the cleavage stage embryo, but either glutathione depletion or oxidation may induce their expression. In untreated embryos, RT-PCR and Western blotting revealed GLCL heavy subunit (GLCL-H) mRNA and protein only at the blastocyst stage of development. Furthermore, while diethyl maleate (DEM) exposure to deplete cellular glutathione did not induce expression of GLCL-H, exposure to tertiary-butyl hydroperoxide (tBH), an oxidizing agent, resulted in significant upregulation of GLCL-H expression in two-cell embryos. Neither treatment affected expression in blastocysts. Finally, HPLC analysis confirmed that tBH-treated embryos experienced oxidative stress, as indicated by an increase in the ratio of oxidized to reduced glutathione. This oxidative stress induced de novo glutathione synthesis in the cleavage stage embryo, as demonstrated by the subsequent recovery of reduced glutathione levels following DEM-induced depletion. In the absence of tBH treatment, however, cleavage stage embryos could not recover GSH after DEM-mediated depletion. This study demonstrates that the preimplantation embryo has the capacity to upregulate glutathione synthesis in response to oxidative stress but not GSH depletion. These results suggest that, while the preimplantation embryo is well adapted to dealing with oxidative stress, it may be poorly protected from GSH-depleting toxicants. SN - 0041-008X UR - https://www.unboundmedicine.com/medline/citation/11032771/Regulation_of_gamma_glutamate_cysteine_ligase_expression_by_oxidative_stress_in_the_mouse_preimplantation_embryo_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0041-008X(00)99030-6 DB - PRIME DP - Unbound Medicine ER -