LexA, a transcription regulator binding in the promoter region of the bidirectional hydrogenase in the cyanobacterium<i>Synechocystis</i>sp. PCC 6803

Oliveira, Paulo; Lindblad, Peter

doi:10.1016/j.femsle.2005.07.024

Cited by 69 publications

(94 citation statements)

References 25 publications

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“…One correlation is between the gene encoding the LexA-like protein (Sll1626) and the hox operon, these genes were upregulated after the transition to low O 2 . This was consistent with the finding that Sll1626 interacts with the hox promoter and positively regulates its expression (Oliveira & Lindblad, 2005). The genes encoding Sll0359 and Sll0882 are also regulators of the hox operon (Ishii & Hihara, 2008;Oliveira & Lindblad, 2008), these genes are not upregulated under low-oxygen conditions, but may play a role in regulation.…”

Section: Resultssupporting

confidence: 90%

“…The LexA-like protein binds two sites in the hydrogenase (hox) operon and may function as a transcription activator (Gutekunst et al, 2005;Oliveira & Lindblad, 2005). Consistent with this, we observed that transcript levels of the hox operon (sll1220-sll1226) increased in both strains under low oxygen (Table 2).…”

Section: The Absence Of Hik31 Alters Transcriptional Response To Low supporting

confidence: 79%

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Gene expression under low-oxygen conditions in the cyanobacterium Synechocystis sp. PCC 6803 demonstrates Hik31-dependent and -independent responses

2011

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We have investigated the response of the cyanobacterium Synechocystis sp. PCC 6803 during growth at very low O 2 concentration (bubbled with 99.9 % N 2 /0.1 % CO 2 ). Significant transcriptional changes upon low-O 2 incubation included upregulation of a cluster of genes that contained psbA1 and an operon that includes a gene encoding the two-component regulatory histidine kinase, Hik31. This regulatory cluster is of particular interest, since there are virtually identical copies on both the chromosome and plasmid pSYSX. We used a knockout mutant lacking the chromosomal copy of hik31 and studied differential transcription during the aerobiclow-O 2 transition in this DHik31 strain and the wild-type. We observed two distinct responses to this transition, one Hik31 dependent, the other Hik31 independent. The Hik31-independent responses included the psbA1 induction and genes involved in chlorophyll biosynthesis. In addition, there were changes in a number of genes that may be involved in assembling or stabilizing photosystem (PS)II, and the hox operon and the LexA-like protein (Sll1626) were upregulated during low-O 2 growth. This family of responses mostly focused on PSII and overall redox control. There was also a large set of genes that responded differently in the absence of the chromosomal Hik31. In the vast majority of these cases, Hik31 functioned as a repressor and transcription was enhanced when Hik31 was deleted. Genes in this category encoded both core and peripheral proteins for PSI and PSII, the main phycobilisome proteins, chaperones, the ATP synthase cluster and virtually all of the ribosomal proteins. These findings, coupled with the fact that DHik31 grew better than the wild-type under low-O 2 conditions, suggested that Hik31 helps to regulate growth and overall cellular homeostasis. We detected changes in the transcription of other regulatory genes that may compensate for the loss of Hik31. We conclude that Hik31 regulates an important series of genes that relate to energy production and growth and that help to determine how Synechocystis responds to changes in O 2 conditions.

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Section: Resultssupporting

confidence: 90%

Section: The Absence Of Hik31 Alters Transcriptional Response To Low supporting

confidence: 79%

Gene expression under low-oxygen conditions in the cyanobacterium Synechocystis sp. PCC 6803 demonstrates Hik31-dependent and -independent responses

2011

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“…4 shows the hydrogenase operon which encodes all proteins required for pentameric bidirectional Ni-Fe hydrogenase (HoxEFUYH). This operon uses a single TSS located 168 nt upstream of hoxE (19), and its regulation is well studied (19)(20)(21). Intriguingly, we found that the operon is framed by two highly expressed ncRNAs, one of which [SyR1 (14)], was strongly upregulated under high light, whereas the other (ncr0700) was maximally expressed in the dark (Fig.…”

Section: Resultsmentioning

confidence: 62%

An experimentally anchored map of transcriptional start sites in the model cyanobacterium Synechocystis sp. PCC6803

Mitschke

Georg

Scholz

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

350

459

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There has been an increasing interest in cyanobacteria because these photosynthetic organisms convert solar energy into biomass and because of their potential for the production of biofuels. However, the exploitation of cyanobacteria for bioengineering requires knowledge of their transcriptional organization. Using differential RNA sequencing, we have established a genome-wide map of 3,527 transcriptional start sites (TSS) of the model organism Synechocystis sp. PCC6803. One-third of all TSS were located upstream of an annotated gene; another third were on the reverse complementary strand of 866 genes, suggesting massive antisense transcription. Orphan TSS located in intergenic regions led us to predict 314 noncoding RNAs (ncRNAs). Complementary microarray-based RNA profiling verified a high number of noncoding transcripts and identified strong ncRNA regulations. Thus, ∼64% of all TSS give rise to antisense or ncRNAs in a genome that is to 87% protein coding. Our data enhance the information on promoters by a factor of 40, suggest the existence of additional small peptide-encoding mRNAs, and provide corrected 5′ annotations for many genes of this cyanobacterium. The global TSS map will facilitate the use of Synechocystis sp. PCC6803 as a model organism for further research on photosynthesis and energy research.gene expression regulation | promoter prediction | RNA polymerase

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“…In Synechocystis sp. PCC 6803, the hoxEFUYH genes are cotranscribed, with the transcription start point located 168 bp upstream of the start codon (87,158). Taking the high diversity of the different cyanobacterial species into account, expression of the bidirectional hydrogenase in cyanobacteria seems to be species specific.…”

Section: Hydrogenases In Cyanobacteria Hydrogenase Types In Cyanobactmentioning

confidence: 99%

Nitrogen Fixation and Hydrogen Metabolism in Cyanobacteria

Bothe

Schmitz²,

Yates

et al. 2010

Microbiol Mol Biol Rev

365

222

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SUMMARY This review summarizes recent aspects of (di)nitrogen fixation and (di)hydrogen metabolism, with emphasis on cyanobacteria. These organisms possess several types of the enzyme complexes catalyzing N2 fixation and/or H2 formation or oxidation, namely, two Mo nitrogenases, a V nitrogenase, and two hydrogenases. The two cyanobacterial Ni hydrogenases are differentiated as either uptake or bidirectional hydrogenases. The different forms of both the nitrogenases and hydrogenases are encoded by different sets of genes, and their organization on the chromosome can vary from one cyanobacterium to another. Factors regulating the expression of these genes are emerging from recent studies. New ideas on the potential physiological and ecological roles of nitrogenases and hydrogenases are presented. There is a renewed interest in exploiting cyanobacteria in solar energy conversion programs to generate H2 as a source of combustible energy. To enhance the rates of H2 production, the emphasis perhaps needs not to be on more efficient hydrogenases and nitrogenases or on the transfer of foreign enzymes into cyanobacteria. A likely better strategy is to exploit the use of radiant solar energy by the photosynthetic electron transport system to enhance the rates of H2 formation and so improve the chances of utilizing cyanobacteria as a source for the generation of clean energy.

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LexA, a transcription regulator binding in the promoter region of the bidirectional hydrogenase in the cyanobacteriumSynechocystissp. PCC 6803

Cited by 69 publications

References 25 publications

Gene expression under low-oxygen conditions in the cyanobacterium Synechocystis sp. PCC 6803 demonstrates Hik31-dependent and -independent responses

Gene expression under low-oxygen conditions in the cyanobacterium Synechocystis sp. PCC 6803 demonstrates Hik31-dependent and -independent responses

An experimentally anchored map of transcriptional start sites in the model cyanobacterium Synechocystis sp. PCC6803

Nitrogen Fixation and Hydrogen Metabolism in Cyanobacteria

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