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J. Biol. Chem., Vol. 280, Issue 40, 33935-33944, October 7, 2005

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 280/40/33935    most recent M503153200v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Cadoret, J.-C. Articles by Houmard, J. Search for Related Content PubMed PubMed Citation Articles by Cadoret, J.-C. Articles by Houmard, J. Social Bookmarking                      What's this?

Cyclic Nucleotides, the Photosynthetic Apparatus and Response to a UV-B Stress in the Cyanobacterium Synechocystis sp. PCC 6803^*

Jean-Charles Cadoret1, Bernard Rousseau, Irène Perewoska, Cosmin Sicora, Otilia Cheregi, Imre Vass, and Jean Houmard2

From the Organismes Photosynthétiques et Environnement, CNRS FRE 2433, Département de Biologie, Ecole Normale Supérieure, 46 rue d'Ulm, 75230 Paris Cedex 05, France and Institute of Plant Biology, Biological Research Centre, P. O. Box 521, 6701 Szeged, Hungary

Cyclic nucleotides cAMP and cGMP are ubiquitous signaling molecules that mediate many adaptative responses in eukaryotic cells. Cyanobacteria present the peculiarity among the prokaryotes of having the two types of cyclic nucleotide. Cellular homeostasis requires both cyclases (adenylyl/guanylyl, for their synthesis) and phosphodiesterases (for their degradation). Fully segregated null mutants have been obtained for the two genes, sll1624 and slr2100, which encode putative cNMP phosphodiesterases. We present physiological evidence that the Synechocystis PCC 6803 open reading frame slr2100 could be a cGMP phosphodiesterase. In addition, we show that Slr2100, but not Sll1624, is required for the adaptation of the cells to a UV-B stress. UV-B radiation has deleterious effects for photosynthetic organisms, in particular on the photosystem II, through damaging the protein structure of the reaction center. Using biophysical and biochemical approaches, it was found that Slr2100 is involved in the signal transduction events which permit the repair of the UV-B-damaged photosystem II. This was confirmed by quantitative reverse transcriptase-PCR analyses. Altogether, the data point to an important role for cGMP in signal transduction and photoacclimation processes during a UV-B stress.

Received for publication, March 22, 2005 , and in revised form, July 22, 2005.

^* This work was supported by grants from the CNRS and IMPB012 BacAttract to the FRE 2433, by Hungarian Granting Agency OTKA Grant T034321, and by European Union Grant STREP-SOLAR-H-516510. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The on-line version of this article (available at http://www.jbc.org) contains supplemental Table 1s.

¹ This research is part of the Ph.D. work performed at Ecole Doctorale B2M and was supported by a bilateral French-Hungarian fellowship.

² To whom correspondence should be addressed. Tel.: 33-1-44-32-3519; Fax: 33-1-44-32-3941; E-mail: jhoumard{at}biologie.ens.fr.

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