Circadian expression data of Synechococcus in WT, rpoD6-null, sasA-null and rpaA-null strains
Ontology highlight
ABSTRACT:
ORGANISM(S): Synechococcus elongatus PCC 7942 = FACHB-805 Synechococcus elongatus PCC 6301
PROVIDER: GSE28430 | GEO | 2012/03/01
SECONDARY ACCESSION(S): PRJNA139149
REPOSITORIES: GEO
Similar Datasets
Project description:In the unicellular cyanobacterium, Synechococcus elongatus PCC 7942, most genes show rhythmic expression controlled by the Kai-based clock under continuous light conditions (LL). We found that rpoD6-null mutants impaired expression of clock-controlled genes peaking at hours 8-10 in LL, while sasA-null or rpaA-null mutants each arrested the expression profiles at subjective dawn. Time-course data (0-24 h) of wild type (WT), rpoD6-null, sasA-null and rpaA-null S. elongatus PCC 7942 strains analyzed under continuous light (LL) conditions after two 12h:12h light:dark (LD) cycles using Affymetrix high-density oligonucleotide microarrays (GeneChip CustomExpress Arrays) representing 2,515 predicted protein-coding genes on the genome of Synechococcus elongatus PCC 6301, which can be used also for the almost homologous strain, S. elongatus PCC 7942.
2012-03-01 | E-GEOD-28430 | biostudies-arrayexpress
Project description:In the unicellular cyanobacteriuIn the cyanobacterium, Synechococcus elongatus PCC 7942, most genes show rhythmic expression controlled by the Kai-based clock under continuous light conditions (LL). Overexpression of clpX led to a decrease in kaiBC promoter activity, disruption of circadian rhythm, and eventually cell death. We found that overexpression of clpX upregulated mRNA levels of ribosomal protein subunits, after which expression of other genes containing the clock genes was decreased. Wild type (WT) and inducible clpX-overexpressor (ox-clpX) S. elongatus PCC 7942 strains were analyzed under continuous light (LL) using Affymetrix high-density oligonucleotide microarrays (GeneChip CustomExpress Arrays) representing predicted 2,515 protein-coding genes on the genome of Synechococcus elongatus PCC 6301, which can be used also to the almost homologous strain, S. elongatus PCC 7942: WT at hours 16 in LL (IPTG-free): WT under LL 20 in LL (addition of 100 µM IPTG for 4 hours): ox-clpX cells at hours 16 in LL (IPTG-free): ox-clpX cells at hours 20 in LL (addition of 100 µM IPTG for 4 hours)
2013-07-31 | E-GEOD-42542 | biostudies-arrayexpress
Project description:Like many other organisms, cyanobacteria exhibit rhythmic gene expression with a period length of 24 hours to adapt to daily environmental changes. In the model organism Synechococcus elongatus PCC 7942 the central oscillator consists of three proteins: KaiA, KaiB and KaiC and utilizes the histidine kinase SasA and its response regulator RpaA as output-signaling pathway. Synechocystis sp. PCC 6803 contains two additional homologs of the kaiB and kaiC genes. Here we demonstrate that RpaA interacts with the core oscillator KaiAB1C1 of Synechocystis sp. PCC 6803 via SasA, similar to Synechococcus elongatus PCC 7942. However, interaction with the additional Kai homologs was not detected, suggesting different signal transduction components for the clock homologs. Inactivation of rpaA in Synechocystis sp. PCC 6803, lead to reduced viability of the mutant in light-dark cycles that aggravated under mixotrophic growth conditions. Chemoheterotrophic growth in the dark was abolished completely. In accordance, transcriptomic data revealed that RpaA is involved in the regulation of genes related to CO2‑acclimation and carbon metabolism under diurnal light conditions. Further, our results indicate that RpaA functions in the posttranslational regulation of glycogen metabolism as well, and a potential link between the circadian clock and motility was identified.
2018-10-01 | GSE116795 | GEO
Project description:In the unicellular cyanobacterium, Synechococcus elongatus PCC 7942, essentially all promoter activities are under the control of the circadian clock in continuous light (LL) conditions. Here, we employed high-density oligonucleotide arrays to explore comprehensive profiles of genome-wide Synechococcus gene expression in wild type, kaiABC-null and kaiC-overexpressor strains under LL and continuous dark (DD) conditions. In the wild type strain more than 30% of transcripts significantly oscillated in a circadian fashion, peaking at subjective dawn and dusk. Such circadian control was nullified in kaiABC-null strains. Although KaiC has been proposed to globally repress gene expression, our analysis revealed that dawn expressing genes were upregulated by kaiC-overexpression, such that the clock was arrested at subjective dawn. Transfer of cells to continuous dark (DD) conditions from LL immediately suppressed expression of most of genes, while the clock keeps time even in the absence of transcriptional feedback. Thus, the Synechococcus genome seems primarily regulated by the light/dark cycles and dramatically modified by the protein-based circadian oscillator. Keywords: timecourse data (~48 hours under continuous light or darkness) from Synechococcus elongatus PCC 7942 (wild type, kaiABC-null, and inducible kaiC-overexpressor) strains Wild type (WT), kaiABC-null (Dkai), and inducible kaiC-overexpressor (oxC) S. elongatus PCC 7942 strains were analyzed under continuous light (LL), continuous dark (DD) using Affymetrix high-density oligonucleotide microarrays (GeneChip CustomExpress Arrays) representing predicted 2,515 protein-coding genes on the genome of Synechococcus elongatus PCC 6301, which can be used also to the almost homologous strain, S. elongatus PCC 7942: Two independent experiments in WT under LL (hours 0 to 52) and DD (hours 0 to 48); Two independent experiments in Dkai under LL (hours 0 to 48); Two independent experiments in oxC under LL in the presence or absence of an inducer, IPTG, from hour 25 to 33 in LL; a single experiment in WT under DD in the presence of an transcriptional inhibitor, rifampicin.
2009-07-31 | E-GEOD-14225 | biostudies-arrayexpress
Project description:In the unicellular cyanobacterium, Synechococcus elongatus PCC 7942, essentially all promoter activities are under the control of the circadian clock in continuous light (LL) conditions. Here, we employed high-density oligonucleotide arrays to investigate comprehensive profiles of genome-wide Synechococcus gene expression in kaiA-overexpressor (Ptrc::[GTG]kaiA) strains under LL. KaiC has been proposed to globally activate gene expression, our analysis revealed that dawn expressing genes were downregulated by kaiA-overexpression, such that the clock was arrested at subjective dawn. IPTG-inducible kaiA-overexpressor (oxA) S. elongatus PCC 7942 strains were analyzed under continuous light (LL) using Affymetrix high-density oligonucleotide microarrays (GeneChip CustomExpress Arrays) representing predicted 2,515 protein-coding genes on the genome of Synechococcus elongatus PCC 6301, which can be used also to the almost homologous strain, S. elongatus PCC 7942: a single experiment in oxA under LL in the presence or absence of an inducer, IPTG, from hour 24 to 48 in LL timecourse data (24~48 hours under continuous light) from Synechococcus elongatus PCC 7942 (inducible kaiA-overexpressor) strains
2013-12-31 | E-GEOD-47015 | biostudies-arrayexpress
Project description:In the unicellular cyanobacterium, Synechococcus elongatus PCC 7942, essentially all promoter activities are under the control of the circadian clock in continuous light (LL) conditions. Here, we employed high-density oligonucleotide arrays to investigate comprehensive profiles of genome-wide Synechococcus gene expression in the kaiCEE mutant strains in which the KaiC phosphorylation cycling is abolished under LL.. In the kaiCEE mutant strain more than 23% of transcripts significantly oscillated with a period of about 48 h. 409 cyclic genes were shared with the wild type strains. kaiCEE mutant strain was analyzed under continuous light (LL) using Affymetrix high-density oligonucleotide microarrays (GeneChip CustomExpress Arrays) representing predicted 2,515 protein-coding genes on the genome of Synechococcus elongatus PCC 6301, which can be used also to the almost homologous strain, S. elongatus PCC 7942: a single experiment in kaiCEE mutant under LL from hour 8 to 96 in LL timecourse data (8~96 hours under continuous light) from Synechococcus elongatus PCC 7942 (kaiCEE mutant) strains
2013-11-28 | E-GEOD-48901 | biostudies-arrayexpress
Project description:The circadian clock of the cyanobacterium Synechococcus elongatus PCC 7942 drives oscillations in global mRNA abundances with 24 hour periodicity under constant light conditions. The transcription factor RpaA, a circadian clock-regulated transcription factor, controls the timing of circadian gene expression, but the mechanisms underlying this control are not well understood. Here we show that four RpaA-dependent sigma factors – RpoD2, RpoD6, RpoD5, and SigF2 – are sequentially activated downstream of active RpaA and are required for proper expression of circadian mRNAs. We find that RpoD6, RpoD5, and SigF2 exhibit circadian oscillations with different timing relative to each other at the level of mRNA expression and protein abundance. By measuring global gene expression in strains modified to individually lack rpoD2, rpoD6, rpoD5, and sigF2 we identify how expression of circadian mRNAs – including sigma factor mRNAs – is altered in the absence of each sigma factor. Broadly, our findings suggest that a single transcription factor, RpaA, is sufficient to generate complex circadian expression patterns in part by regulating an interdependent sigma factor cascade.
2019-05-20 | GSE114693 | GEO
Project description:In the unicellular cyanobacterium, Synechococcus elongatus PCC 7942, essentially all promoter activities are under the control of the circadian clock in continuous light (LL) conditions. Here, we employed high-density oligonucleotide arrays to explore comprehensive profiles of genome-wide Synechococcus gene expression in wild type, kaiABC-null and kaiC-overexpressor strains under LL and continuous dark (DD) conditions. In the wild type strain more than 30% of transcripts significantly oscillated in a circadian fashion, peaking at subjective dawn and dusk. Such circadian control was nullified in kaiABC-null strains. Although KaiC has been proposed to globally repress gene expression, our analysis revealed that dawn expressing genes were upregulated by kaiC-overexpression, such that the clock was arrested at subjective dawn. Transfer of cells to continuous dark (DD) conditions from LL immediately suppressed expression of most of genes, while the clock keeps time even in the absence of transcriptional feedback. Thus, the Synechococcus genome seems primarily regulated by the light/dark cycles and dramatically modified by the protein-based circadian oscillator. Keywords: timecourse data (~48 hours under continuous light or darkness) from Synechococcus elongatus PCC 7942 (wild type, kaiABC-null, and inducible kaiC-overexpressor) strains
2009-08-01 | GSE14225 | GEO
Project description:In the unicellular cyanobacteriuIn the cyanobacterium, Synechococcus elongatus PCC 7942, most genes show rhythmic expression controlled by the Kai-based clock under continuous light conditions (LL). Overexpression of clpX led to a decrease in kaiBC promoter activity, disruption of circadian rhythm, and eventually cell death. We found that overexpression of clpX upregulated mRNA levels of ribosomal protein subunits, after which expression of other genes containing the clock genes was decreased.
2013-07-31 | GSE42542 | GEO
Project description:In the unicellular cyanobacterium, Synechococcus elongatus PCC 7942, most of genes are downregulated in the dark, while 10% of genes are upregulated. Here, we employed high-density oligonucleotide arrays to explore comprehensive profiles of genome-wide Synechococcus gene expression in wild type and kaiABC-null strains under continuous dark (DD) conditions. We found that expression profile of a subset of genes on the genome in DD was dramatically affected by kaiABC-nullification, and the magnitude of dark-induction was dependent on time when cells were transferred from light to DD Keywords: timecourse data (0-12 h) under continuous darkness after dark:light cycles from Synechococcus elongatus PCC 7942 wild type and kaiABC-null strains Wild type (WT) and kaiABC-null (DkaiABC) S. elongatus PCC 7942 strains were analyzed under continuous dark (DD) conditions after two 12h:12h light:dark (LD) cycles using Affymetrix high-density oligonucleotide microarrays (GeneChip CustomExpress Arrays) representing predicted 2,515 protein-coding genes on the genome of Synechococcus elongatus PCC 6301, which can be used also to the almost homologous strain, S. elongatus PCC 7942: Two independent experiments in WT and Dkai strains under DD (hours 0, 0.5, 1, 2, 4, 8 and 12).
2011-09-29 | E-GEOD-22468 | biostudies-arrayexpress