Immunocytochemical localization of the stress-induced DpsA protein in the cyanobacterium Synechococcus sp. strain PCC 7942

Durham, Kathryn A.; Bullerjahn, George S.

doi:10.1002/1521-4028(200212)42:6<367::aid-jobm367>3.0.co;2-t

Cited by 18 publications

(13 citation statements)

References 17 publications

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“…In Synechococcus sp. strain PCC 7942, dpsA (the mrgA homologue) transcripts accumulated in the stationary phase and under most nutrient stress conditions (13,46,56), and a strain lacking dpsA was more sensitive to peroxide (14). The mrgA gene in Synechocystis sp.…”

Section: Discussionmentioning

confidence: 99%

Differential Gene Expression in Response to Hydrogen Peroxide and the Putative PerR Regulon ofSynechocystissp. Strain PCC 6803

Li¹,

Singh²,

et al. 2004

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We utilized a full genome cDNA microarray to identify the genes that comprise the peroxide stimulon in the cyanobacterium Synechocystis sp. strain PCC 6803. We determined that a gene (slr1738) encoding a protein similar to PerR in Bacillus subtilis was induced by peroxide. We constructed a PerR knockout strain and used it to help identify components of the PerR regulon, and we found that the regulatory properties were consistent with the hypothesis that PerR functions as a repressor. This effort was guided by finding putative PerR boxes in positions upstream of specific genes and by careful statistical analysis. PerR and sll1621 (ahpC), which codes for a peroxiredoxin, share a divergent promoter that is regulated by PerR. We found that isiA, encoding a Chl protein that is induced under low-iron conditions, was strongly induced by a short-term peroxide stress. Other genes that were strongly induced by peroxide included sigD, sigB, and genes encoding peroxiredoxins and Dsb-like proteins that have not been studied yet in this strain. A gene (slr1894) that encoded a protein similar to MrgA in B. subtilis was upregulated by peroxide, and a strain containing an mrgA knockout mutation was highly sensitive to peroxide. A number of genes were downregulated, including key genes in the chlorophyll biosynthesis pathway and numerous regulatory genes, including those encoding histidine kinases. We used PerR mutants and a thioredoxin mutant (TrxA1) to study differential expression in response to peroxide and determined that neither PerR nor TrxA1 is essential for the peroxide protective response.

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Section: Discussionmentioning

confidence: 99%

Differential Gene Expression in Response to Hydrogen Peroxide and the Putative PerR Regulon ofSynechocystissp. Strain PCC 6803

Li¹,

Singh²,

et al. 2004

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“…This is intriguing in the light of the reported sequestration of Fe 2 + in D. radiodurans [11]; whereas Mn 2 + , which accumulates to millimolar concentrations is globally distributed, Fe 2 + is largely sequestered outside the cytoplasm in a region overlapping the septum between dividing cells. has been shown to have a non-cytoplasmic localization, partitioning to the thylakoid membrane where a role in metal transport was proposed [48]. Only DpsA from Synechococcus sp.…”

Section: Dps-2 Is Non-cytoplasmically Localizedmentioning

confidence: 99%

Functional comparison of Deinococcus radiodurans Dps proteins suggests distinct in vivo roles

Reon

Nguyen

Bhattacharyya

et al. 2012

Biochemical Journal

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Deinococcus radiodurans exhibits extreme resistance to DNA damage and is one of only few bacteria that encode two Dps (DNA protection during starvation) proteins. Dps-1 was shown previously to bind DNA with high affinity and to localize to the D. radiodurans nucleoid. A unique feature of Dps-2 is its predicted signal peptide. In the present paper, we report that Dps-2 assembly into a dodecamer requires the C-terminal extension and, whereas Dps-2 binds DNA with low affinity, it protects against degradation by reactive oxygen species. Consistent with a role for Dps-2 in oxidative stress responses, the Dps-2 promoter is up-regulated by oxidative stress, whereas the Dps-1 promoter is not. Although DAPI (4',6-diamidino-2-phenylindole) staining of Escherichia coli nucleoids shows that Dps-1 can compact genomic DNA, such nucleoid condensation is absent from cells expressing Dps-2. A fusion of EGFP (enhanced green fluorescent protein) to the Dps-2 signal peptide results in green fluorescence at the perimeter of D. radiodurans cells. The differential response of the Dps-1 and Dps-2 promoters to oxidative stress, the distinct cellular localization of the proteins and the differential ability of Dps-1 and Dps-2 to attenuate hydroxyl radical production suggest distinct functional roles; whereas Dps-1 may function in DNA metabolism, Dps-2 may protect against exogenously derived reactive oxygen species.

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“…In Synechococcus sp. PCC 7942, while an insoluble DpsA fraction would bind DNA, a soluble faction, localized into the thylakoid membranes, would allow maintaining metal homeostasis of the photosynthetic apparatus (Durham and Bullerjahn, 2002). Thus, as the Cu/Zn-SOD, DpsA would confer a better resistance of HL cells to the ROS generated within the thylakoid membrane.…”

Section: Transcriptome Response To Oxidative Stressmentioning

confidence: 99%

Light History Influences the Response of the Marine CyanobacteriumSynechococcussp. WH7803 to Oxidative Stress

et al. 2011

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Marine Synechococcus undergo a wide range of environmental stressors, especially high and variable irradiance, which may induce oxidative stress through the generation of reactive oxygen species (ROS). While light and ROS could act synergistically on the impairment of photosynthesis, inducing photodamage and inhibiting photosystem II repair, acclimation to high irradiance is also thought to confer resistance to other stressors. To identify the respective roles of light and ROS in the photoinhibition process and detect a possible light-driven tolerance to oxidative stress, we compared the photophysiological and transcriptomic responses of Synechococcus sp. WH7803 acclimated to low light (LL) or high light (HL) to oxidative stress, induced by hydrogen peroxide (H 2 O 2 ) or methylviologen. While photosynthetic activity was much more affected in HL than in LL cells, only HL cells were able to recover growth and photosynthesis after the addition of 25 mM H 2 O 2 . Depending upon light conditions and H 2 O 2 concentration, the latter oxidizing agent induced photosystem II inactivation through both direct damage to the reaction centers and inhibition of its repair cycle. Although the global transcriptome response appeared similar in LL and HL cells, some processes were specifically induced in HL cells that seemingly helped them withstand oxidative stress, including enhancement of photoprotection and ROS detoxification, repair of ROS-driven damage, and regulation of redox state. Detection of putative LexA binding sites allowed the identification of the putative LexA regulon, which was downregulated in HL compared with LL cells but up-regulated by oxidative stress under both growth irradiances.

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Immunocytochemical localization of the stress-induced DpsA protein in the cyanobacterium Synechococcus sp. strain PCC 7942

Cited by 18 publications

References 17 publications

Differential Gene Expression in Response to Hydrogen Peroxide and the Putative PerR Regulon ofSynechocystissp. Strain PCC 6803

Differential Gene Expression in Response to Hydrogen Peroxide and the Putative PerR Regulon ofSynechocystissp. Strain PCC 6803

Functional comparison of Deinococcus radiodurans Dps proteins suggests distinct in vivo roles

Light History Influences the Response of the Marine CyanobacteriumSynechococcussp. WH7803 to Oxidative Stress

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