GENES: STRUCTURE AND REGULATION
Glutathione Redox Potential Modulated by Reactive Oxygen Species Regulates Translation of Rubisco Large Subunit in the Chloroplast*

https://doi.org/10.1074/jbc.275.21.16289Get rights and content
Under a Creative Commons license
open access

Previous work showed a transient but dramatic arrest in the synthesis of Rubisco large subunit (LSU) upon transfer ofChlamydomonas reinhardtii cells from low light (LL) to high light (HL). Using dichlorofluorescin, a short-term increase in reactive oxygen species (ROS) was demonstrated, suggesting that their excessive formation could signal LSU down-regulation. A decrease in LSU synthesis occurred at LL in the presence of methyl viologen and was prevented at HL by ascorbate. Interfering with D1 function by mutations or by incubation with DCMU prevented the increase in ROS formation at HL and the concomitant down-regulation of LSU synthesis. If the electron transport was blocked further downstream, by mutation in the cytochromeb 6/f or by incubation with 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone, ROS formation increased, and LSU synthesis ceased. The elevation of ROS occurred concurrently with a change in the redox state of the glutathione pool, which shifted toward its oxidized form immediately after the transfer to HL and returned to its original value after 6 h. The decrease in the reduced/oxidized glutathione ratio at HL was prevented by ascorbate and could be induced at LL by methyl viologen. We suggest that excess ROS mediate a decrease in the reduced/oxidized glutathione ratio that in turn signals the translational arrest of the rbcL transcript.

Cited by (0)

*

This work was supported by the Doris and Bertie Black Center for Bioenergetics in Life Sciences at the Ben-Gurion University.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.