Transcriptional analysis of the isiAB operon in salt-stressed cells of the cyanobacterium Synechocystis sp. PCC 6803

Vinnemeier, Josef

doi:10.1016/s0378-1097(98)00478-9

Cited by 47 publications

(86 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition to its response to iron limitation, IsiA of Synechocystis sp. strain PCC 6803 responded to salt stress (2,3,66,67), and we show here that isiA and isiB are highly induced by short-term oxidative stress, even in the presence of low peroxide concentrations (data not shown). This implies that induction of isiA is initiated long before IsiA is used as an antenna for a smaller number of PSI units.…”

Section: Discussionmentioning

confidence: 57%

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

Li¹,

Singh²,

et al. 2004

View full text Add to dashboard Cite

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.

show abstract

Section: Discussionmentioning

confidence: 57%

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

Li¹,

Singh²,

et al. 2004

View full text Add to dashboard Cite

show abstract

“…The induction of CP43# was tested during exposure of the cells to 0.7 M NaCl or 5 mM H 2 O 2 as well. These conditions were reported to induce isiA transcription (Vinnemeier et al, 1998;Yousef et al, 2003). However, no differential effect on CP43# fluorescence in the mutant cultures could be observed in these experiments (Table I).…”

Section: Resultsmentioning

confidence: 62%

“…In addition to iron, isiA transcription was found to be regulated by salt and oxidative stresses (Vinnemeier et al, 1998;Yousef et al, 2003, respectively).…”

Section: Resultsmentioning

confidence: 99%

Critical Roles of Bacterioferritins in Iron Storage and Proliferation of Cyanobacteria

2004

View full text Add to dashboard Cite

Cyanobacteria are key contributors to global photosynthetic productivity, and iron availability is essential for cyanobacterial proliferation. While iron is abundant in the earth's crust, its unique chemical properties render it a limiting factor for photoautotrophic growth. As compared to other nonphotosynthetic organisms, oxygenic photosynthetic organisms such as cyanobacteria, algae, and green plants need large amounts of iron to maintain functional PSI complexes in their photosynthetic apparatus. Ferritins and bacterioferritins are ubiquitously present iron-storage proteins. We have found that in the cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis 6803), bacterioferritins are responsible for the storage of as much as 50% of cellular iron. Synechocystis 6803, as well as many other cyanobacterial species, have two bacterioferritins, BfrA and BfrB, in which either the heme binding or di-iron center ligating residues are absent. Purified bacterioferritin complex from Synechocystis 6803 has both BfrA and BfrB proteins. Targeted mutagenesis of each of the two bacterioferritin genes resulted in poor growth under iron-deprived conditions. Inactivation of both genes did not result in a more severe phenotype. These results support the presence of a heteromultimeric structure of Synechocystis bacterioferritin, in which one subunit ligates a diiron center while the other accommodates heme binding. Notably, the reduced internal iron concentrations in the mutant cells resulted in a lower content of PSI. In addition, they triggered iron starvation responses even in the presence of normal levels of external iron, thus demonstrating a central role of bacterioferritins in iron homeostasis in these photosynthetic organisms.Iron serves as a cofactor in a multitude of cellular processes. As such, iron accumulation and storage processes are essential for the survival of all organisms. However, the same redox properties that make iron a valuable cofactor also lead to oxidative interactions resulting in the formation of harmful radicals. Therefore, iron accumulation in the cells is tightly regulated to ensure that very little free iron is present (Kakhlon and Cabantchik, 2002).While iron is abundant in the earth's crust, the bioavailability of iron in the current oxidative terrestrial environment is limited. This is due to the fact that in the presence of dioxygen at neutral pH, iron precipitates as Fe(OH) 3 . As a consequence, the bioavailability of iron limits the proliferation of photosynthetic organisms. Indeed, studies conducted in the Southern Ocean have indicated that iron is a limiting factor for primary photosynthetic productivity (Falkowski et al., 1998). In many of the ecological niches occupied by photosynthetic organisms, iron concentrations are limited to nanomolar levels (Morel and Price, 2003). Surges in the iron concentration due to aeolian dust deposition are transient (Falkowski et al., 1998). To accommodate such an infrequent supply of iron, photosynthetic organisms must have efficient iron storage mec...

show abstract

“…IsiA also protects PSII and PSI against the damage caused by excessive light through a nonradiative type of energy dissipation (Ivanov et al, 2000(Ivanov et al, , 2006Sandströ m et al, 2001Sandströ m et al, , 2002Ihalainen et al, 2005). Besides its expression under low Fe concentrations and during conditions of oxidative stress (Jeanjean et al, 2003;Yousef et al, 2003;Li et al, 2004;Michel and Pistorius, 2004;Singh et al, 2004), IsiA is also expressed in high amounts during sodium chloride stress (Vinnemeier et al, 1998;Havaux et al, 2005), heat stress (Fulda et al, 2006), and during the stationary growth phase (Singh and Sherman, 2006). The expression of IsiA in Synechococcus elongatus PCC 7942 is thought to be regulated by the transcriptional repressor Fur (Ghassemian and Straus, 1996).…”

mentioning

confidence: 99%

Transcript Profiling Reveals New Insights into the Acclimation of the Mesophilic Fresh-Water CyanobacteriumSynechococcus elongatusPCC 7942 to Iron Starvation

Nodop

Pietsch²,

Höcker³

et al. 2008

Plant Physiology

View full text Add to dashboard Cite

The regulatory network for acclimation of the obligate photoautotrophic fresh water cyanobacterium Synechococcus elongatus PCC 7942 to iron (Fe) limitation was studied by transcript profiling with an oligonucleotide whole genome DNA microarray. Six regions on the chromosome with several Fe-regulated genes each were identified. The irpAB and fut region encode putative Fe uptake systems, the suf region participates in [Fe-sulfur] cluster assembly under oxidative stress and Fe limitation, the isiAB region encodes CP43# and flavodoxin, the idiCB region encodes the NuoE-like electron transport associated protein IdiC and the transcriptional activator IdiB, and the ackA/pgam region encodes an acetate kinase and a phosphoglycerate mutase. We also investigated the response of two S. elongatus PCC 7942 mutants to Fe starvation. These were mutant K10, lacking IdiB but containing IdiC, and mutant MuD, representing a idiC-merodiploid mutant with a strongly reduced amount of IdiC as well as IdiB. The absence of IdiB in mutant K10 or the strongly reduced amount of IdiB in mutant MuD allowed for the identification of additional members of the Fe-responsive IdiB regulon. Besides idiA and the irpAB operon somB(1), somA(2), ftr1, ackA, pgam, and nat also seem to be regulated by IdiB. In addition to the reduced amount of IdiB in MuD, the low concentration of IdiC may be responsible for a number of additional changes in the abundance of mainly photosynthesis-related transcripts as compared to the wild type and mutant K10.

show abstract

Transcriptional analysis of the isiAB operon in salt-stressed cells of the cyanobacterium Synechocystis sp. PCC 6803

Cited by 47 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

Critical Roles of Bacterioferritins in Iron Storage and Proliferation of Cyanobacteria

Transcript Profiling Reveals New Insights into the Acclimation of the Mesophilic Fresh-Water CyanobacteriumSynechococcus elongatusPCC 7942 to Iron Starvation

Contact Info

Product

Resources

About