Elucidating the direct target regulon of NtcA during the early acclimation to nitrogen starvation in the cyanobacterium Synechocystis sp. PCC 6803
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PROVIDER: PRJNA381208 | ENA |
REPOSITORIES: ENA
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Project description:Cyanobacteria are oxygenic photoautotrophs responsible for a substantial proportion of nitrogen fixation and primary production in the hydrosphere. Non-nitrogen fixing cyanobacteria, such as Synechocystis sp. PCC 6803, depend of the availability of nitrogenized species to survive. Therefore, an intricate regulatory network around the transcriptional factor NtcA maintains the homeostasis of nitrogen in these organisms. The mechanisms controlling NtcA activity are well understood but a comprehensive study of its regulon is missing in Synechocystis. To define NtcA regulon during the early stage of nitrogen starvation, we have performed chromatin immunoprecipitation followed by sequencing (ChiP-seq), in parallel with genome level transcriptome analysis (RNA-seq). By combining both methods we assigned 51 activated and 28 repressed genes directly by NtcA. Most of direct targets included genes involved in nitrogen and carbon metabolism and photosynthesis. NtcA regulon also included 8 ncRNAs, of which ncr0710, Syr6 and NsiR7 were experimentally validated. Intriguingly, we identified several NtcA intragenic binding sites suggesting that NtcA can modulate transcriptional expression by binding along the whole transcript and not only in the promoter region as previously though. Finally, the transcriptional implication of PipX was analyzed in some NtcA-targets genes, revealing that PipX assists NtcA in the global nitrogen regulation in Synechocystis.
2017-10-01 | GSE97282 | GEO
Project description:Cyanobacteria are oxygenic photoautotrophs responsible for a substantial proportion of nitrogen fixation and primary production in the hydrosphere. Non-nitrogen fixing cyanobacteria, such as Synechocystis sp. PCC 6803, depend of the availability of nitrogenized species to survive. Therefore, an intricate regulatory network around the transcriptional factor NtcA maintains the homeostasis of nitrogen in these organisms. The mechanisms controlling NtcA activity are well understood but a comprehensive study of its regulon is missing in Synechocystis. To define NtcA regulon during the early stage of nitrogen starvation, we have performed chromatin immunoprecipitation followed by sequencing (ChiP-seq), in parallel with genome level transcriptome analysis (RNA-seq). By combining both methods we assigned 51 activated and 28 repressed genes directly by NtcA. Most of direct targets included genes involved in nitrogen and carbon metabolism and photosynthesis. NtcA regulon also included 8 ncRNAs, of which ncr0710, Syr6 and NsiR7 were experimentally validated. Intriguingly, we identified several NtcA intragenic binding sites suggesting that NtcA can modulate transcriptional expression by binding along the whole transcript and not only in the promoter region as previously though. Finally, the transcriptional implication of PipX was analyzed in some NtcA-targets genes, revealing that PipX assists NtcA in the global nitrogen regulation in Synechocystis.
2017-10-01 | GSE97289 | GEO
Project description:Every cyanobacterial species contains gene encoding site-2-protease (S2P) homolog. The studied prokaryotic S2P homologs play essential roles in regulating stress response through intramembrane proteolysis of membrane-bound anti-sigma factors. Here, gene of Slr0643, one of four S2P homologs in Synechocystis sp. PCC 6803, was insertionally disrupted to explore its physiological role. Only a partially segregated mutant was obtained, indicating its indispensability for growth. The partially disrupted mutant could not grow at pH 6.5, while wild type acclimated to pH 6.5 quickly. The slr0643 gene expression was transiently induced after pH transfer from 7.5 to 6.5. Both evidences demonstrated the pivotal role of fully functional Slr0643 in acid acclimation. DNA microarray and quantitative RT-PCR analyses decoded genes involved in early acid acclimation and revealed differentially expressed genes due to slr0643 disruption at both pH conditions. Early acid acclimation to pH 6.5 included upregulation of sigH, hik16 and hik35, and downregulation of pcrR and sigG; as well as downregulation of porins and upregulation of inorganic carbon and nitrogen transporters. Defective photosynthesis and excess expression of NADH dehydrogenase, together with over upregulation of carbon transporter and repression of nitrogen transporter and metabolism gene contributed to the acid lethality of mutant at pH 6.5. Most interestingly, analysis of microarray data revealed the close relationship between slr0643 disruption and expression of sigH operon. Therefore it was implied that Slr0643/Sll0857/SigH might acts through S2P/anti-Sigma factor/Sigma factor mechanism to play a role in acid acclimation.
2012-09-18 | GSE37747 | GEO
Project description:Every cyanobacterial species contains gene encoding site-2-protease (S2P) homolog. The studied prokaryotic S2P homologs play essential roles in regulating stress response through intramembrane proteolysis of membrane-bound anti-sigma factors. Here, gene of Slr0643, one of four S2P homologs in Synechocystis sp. PCC 6803, was insertionally disrupted to explore its physiological role. Only a partially segregated mutant was obtained, indicating its indispensability for growth. The partially disrupted mutant could not grow at pH 6.5, while wild type acclimated to pH 6.5 quickly. The slr0643 gene expression was transiently induced after pH transfer from 7.5 to 6.5. Both evidences demonstrated the pivotal role of fully functional Slr0643 in acid acclimation. DNA microarray and quantitative RT-PCR analyses decoded genes involved in early acid acclimation and revealed differentially expressed genes due to slr0643 disruption at both pH conditions. Early acid acclimation to pH 6.5 included upregulation of sigH, hik16 and hik35, and downregulation of pcrR and sigG; as well as downregulation of porins and upregulation of inorganic carbon and nitrogen transporters. Defective photosynthesis and excess expression of NADH dehydrogenase, together with over upregulation of carbon transporter and repression of nitrogen transporter and metabolism gene contributed to the acid lethality of mutant at pH 6.5. Most interestingly, analysis of microarray data revealed the close relationship between slr0643 disruption and expression of sigH operon. Therefore it was implied that Slr0643/Sll0857/SigH might acts through S2P/anti-Sigma factor/Sigma factor mechanism to play a role in acid acclimation. M-bM-^@M-^C Loop design was used to compare differential expression of wild type and mutant at pH 7.5 and pH 6.5 respectively, including dye-swape. Biological variation was sampled by extracting RNA from three independent experiments and pooling them together before hybridizations. Two or four replicate chips for each comparison and two replicate printings per chip represent technical repeats.
2012-09-18 | E-GEOD-37747 | biostudies-arrayexpress
Project description:Acclimation to low CO2 conditions in cyanobacteria involves the coordinated regulation of genes mainly encoding components of the carbon concentration mechanism (CCM). Making use of several independent microarray datasets a core set of CO2-regulated genes was defined for the model strain Synechocystis sp. PCC 6803. On the transcriptional level, the CCM is mainly regulated by the well-characterized transcriptional regulators NdhR and CmpR, whereas the role of an additional regulatory protein, namely cyAbrB2 belonging to the widely distributed AbrB regulator family that was originally characterized in the genus Bacillus, is less defined. Here we present results of transcript profiling of the wild type and a ΔcyabrB2 mutant of Synechocystis sp. PCC 6803 after shifts from high CO2 (5% in air, HC) to low CO2 (0.04%, LC). Evaluation of the transcriptomic data revealed that cyAbrB2 is involved in the regulation of several CCM-related genes such as sbtA/B, ndhF3/ndhD3/cupA and cmpABCD under LC conditions, but apparently acts supplementary to the main regulators. Under HC conditions, cyAbrB2 deletion changes the expression of photosystem II subunits, light-harvesting components, and Calvin-Benson-Bassham cycle enzymes.
2016-09-19 | GSE82120 | GEO
Project description:Regulation of gene expression is a sophisticated process leading to the activation or suppression of genes due to adaptation to environmental stimuli. The membrane-embedded FtsH proteases conserved in bacteria, chloroplasts and mitochondria, are involved in such regulation. The genome of the cyanobacterium Synechocystis sp. PCC 6803 encodes four FtsH homologues FtsH1-4, functioning in the form of oligomeric complexes. Homologue FtsH3 is bound in two hetero-oligomeric complexes, FtsH1/FstH3 and/or FtsH2/FtsH3, respectively. Previous data showed that the FtsH1/FtsH3 complex is involved in the acclimation of cells to iron deficiency by controlling the availability of the transcriptional regulator Fur (Sll0567). To gain more comprehensive insight into the physiological role of FtsH hetero-complexes, we carried out genome-wide expression profiling of a mutant conditionally depleted in FtsH3, grown under nutrient sufficiency and iron depletion. Our results show, that besides Fur, also the SufR and Pho regulons belong to the set of genes controlled by FtsH. Moreover, by combining the transcriptome data with in silico prediction we identified novel targets of Fur in Synechocystis PCC 6803. Fur tends to evoke mostly repression, but also appears to activate some target genes. We monitored the global gene expression in a conditional Synechocystis PCC6083 ftsH knockdown strain (FtsHdown) (Boehm et al., 2012) and a control strain (WT) at standard conditions and at iron depletion. The presence of ammonia to induced the conditional knockdown. Each sample was done in biological replicates.
2016-06-14 | E-GEOD-83303 | biostudies-arrayexpress
Project description:To investigate acclimation mechanisms employed under extreme high light conditions, gene expression analysis was performed using the model microalgae Synechocystis sp. PCC 6803 (PCC 6803) cultured under various light intensities. From the low to the mid light conditions, the expression of genes related to light harvesting systems was repressed, whereas that of CO2 fixation and of D1 protein turnover-related genes was induced. Gene expression data also revealed that the down-regulation of genes related to flagellum synthesis (pilA2), pyridine nucleotide transhydrogenase (pntA and pntB), and sigma factor (sigA and sigF) represents acclimation mechanisms of PCC 6803 under excessive high light conditions.
2018-03-06 | GSE111408 | GEO
Project description:Elucidating the direct target regulon of NtcA during the early acclimation to nitrogen starvation in the cyanobacterium Synechocystis sp. PCC 6803 [ChIP-Seq]
| PRJNA381199 | ENA
Project description:Elucidating the direct target regulon of NtcA during the early acclimation to nitrogen starvation in the cyanobacterium Synechocystis sp. PCC 6803 [RNA-Seq]
| PRJNA381210 | ENA
Project description:Regulation of gene expression is a sophisticated process leading to the activation or suppression of genes due to adaptation to environmental stimuli. The membrane-embedded FtsH proteases conserved in bacteria, chloroplasts and mitochondria, are involved in such regulation. The genome of the cyanobacterium Synechocystis sp. PCC 6803 encodes four FtsH homologues FtsH1-4, functioning in the form of oligomeric complexes. Homologue FtsH3 is bound in two hetero-oligomeric complexes, FtsH1/FstH3 and/or FtsH2/FtsH3, respectively. Previous data showed that the FtsH1/FtsH3 complex is involved in the acclimation of cells to iron deficiency by controlling the availability of the transcriptional regulator Fur (Sll0567). To gain more comprehensive insight into the physiological role of FtsH hetero-complexes, we carried out genome-wide expression profiling of a mutant conditionally depleted in FtsH3, grown under nutrient sufficiency and iron depletion. Our results show, that besides Fur, also the SufR and Pho regulons belong to the set of genes controlled by FtsH. Moreover, by combining the transcriptome data with in silico prediction we identified novel targets of Fur in Synechocystis PCC 6803. Fur tends to evoke mostly repression, but also appears to activate some target genes.
2016-06-14 | GSE83303 | GEO