Chlamydomonas reinhardtii
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PROVIDER: PRJNA154675 | ENA |
REPOSITORIES: ENA
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Project description:To identify components involved in the signal transduction and activation of the singlet oxygen-mediated response, a mutant selection was performed. This led to the isolation of the singlet oxygen resistant 1 (sor1) mutant, which is more tolerant to singlet oxygen-producing chemicals and shows a constitutively higher expression of GPXH and GSTS1. Map-based cloning revealed that the SOR1 gene encodes a novel bZIP transcription factor, which seems to control its own expression as well as that of a large number of oxidative stress response and detoxification genes. In the promoter region of many of these genes a highly conserved 8-bp palindromic sequence element was found to be enriched. This element was shown to be essential for GSTS1 overexpression in sor1 and for induction by increased levels of lipophilic reactive electrophile species (RES) suggesting that it functions as an electrophile response element (ERE). RES can be formed after singlet oxygen-induced lipid peroxidation, indicating that a RES-stimulated and SOR1-mediated response of detoxification genes is part of the singlet oxygen-induced acclimation process in C. reinhardtii.
2012-04-03 | GSE33548 | GEO
Project description:To identify components involved in the signal transduction and activation of the singlet oxygen-mediated response, a mutant selection was performed. This led to the isolation of the singlet oxygen resistant 1 (sor1) mutant, which is more tolerant to singlet oxygen-producing chemicals and shows a constitutively higher expression of GPXH and GSTS1. Map-based cloning revealed that the SOR1 gene encodes a novel bZIP transcription factor, which seems to control its own expression as well as that of a large number of oxidative stress response and detoxification genes. In the promoter region of many of these genes a highly conserved 8-bp palindromic sequence element was found to be enriched. This element was shown to be essential for GSTS1 overexpression in sor1 and for induction by increased levels of lipophilic reactive electrophile species (RES) suggesting that it functions as an electrophile response element (ERE). RES can be formed after singlet oxygen-induced lipid peroxidation, indicating that a RES-stimulated and SOR1-mediated response of detoxification genes is part of the singlet oxygen-induced acclimation process in C. reinhardtii. The sor1 mutant isolated in a screen for singlet oxygen resistant mutants and the corresponding wild-type strain 4A+ were grown in a 12 h light dark cycle for several days before total RNA was extracted 6 h after the light came on.
2012-04-03 | E-GEOD-33548 | biostudies-arrayexpress
Project description:Acclimation to singlet oxygen was shown to induce various oxidative stress response genes of which some were also strongly overexpressed in the singlet oxygen resistant mutant sor1. Because sor1 was also more tolerant to other oxidative and electrophilic stress conditions, and because many of the sor1 overexpressed genes are known to be involved in the detoxification of reactive electrophile species, the response of the C. reinhardtii wild-type strain to various oxidative and electrophilic stress conditions was determined. Therefore, cultures were exposed to the reactive oxygen species-producing photosensitizer neutral red, the organic hydroperoxide tert-butylhydroperoxide, the photosynthetic herbicide 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB) and the lipophilic electrophile 2(E)-Hexenal for two hours and the global genetic response was analyzed. Cluster analysis revealed the most similar expression pattern between DBMIB and 2(E)-Hexenal and to a lower degree between NR and tBOOH. Still, there were many common induced genes including several of the oxidative stress response and detoxification genes overexpressed in the sor1 mutant.
2011-07-15 | GSE30646 | GEO
Project description:SINGLET OXYGEN RESISTANT 1 links reactive electrophile signaling to singlet oxygen acclimation in Chlamydomonas reinhardtii
| PRJNA148881 | ENA
Project description:Acclimation to singlet oxygen was shown to induce various oxidative stress response genes of which some were also strongly overexpressed in the singlet oxygen resistant mutant sor1. Because sor1 was also more tolerant to other oxidative and electrophilic stress conditions, and because many of the sor1 overexpressed genes are known to be involved in the detoxification of reactive electrophile species, the response of the C. reinhardtii wild-type strain to various oxidative and electrophilic stress conditions was determined. Therefore, cultures were exposed to the reactive oxygen species-producing photosensitizer neutral red, the organic hydroperoxide tert-butylhydroperoxide, the photosynthetic herbicide 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB) and the lipophilic electrophile 2(E)-Hexenal for two hours and the global genetic response was analyzed. Cluster analysis revealed the most similar expression pattern between DBMIB and 2(E)-Hexenal and to a lower degree between NR and tBOOH. Still, there were many common induced genes including several of the oxidative stress response and detoxification genes overexpressed in the sor1 mutant. The 4A+ wild-type strain was grown mixotrophically in a Tris-acetate phosphate to a density of 2x10^6 cells/ml. Then cultures were split into 20 ml subcultures, and exposed to either of the four chemicals DBMIB (2 µM), 2(E)-Hexenal (0.3 mM), neutral red (NR, 3 µM), tert-butylhydroperoxide (tBOOH, 100 µM) or no chemical (control) for 2 hours, in three independent biological replicates. The cells of each replicate were harvested by centrifugation and total RNA was isolated using the RNeasy Mini Kit (Qiagen). DNA microarrays were performed using the ‘One-Color Microarray-Based Gene Expression Analysis’ system and a custom made 4 × 44 K ‘Chlamydomonas Whole Genome DNA Microarrays’ (Agilent Technologies) containing 15143 specific probes designed based on the Chlamydomonas version 4.0 transcript models provided by the DOE Joint Genome Institute (JGI), with an average of three replicates for each probe
2011-07-14 | E-GEOD-30646 | biostudies-arrayexpress
Project description:We identified a small zinc finger protein, MBS, as a new mediator of singlet oxygen responses in Chlamydomonas and Arabidopsis. MBS is required for induction of singlet oxygen-dependent gene expression and, upon oxidative stress, accumulates in distinct granules in the cytosol of Arabidopsis cells. First, we recorded changes in light stress-regulated gene expression profiles after genetically perturbing MBS function by isolating mutants for the two MBS genes (MBS1 and MBS2) and by overexpression of MBS1 in Arabidopsis thaliana. Then, these light stress-related gene expression profiles were analyzed with respect to genes specifically responding to singlet oxygen and hydrogen peroxide/superoxide. The results indicated that MBS inactivation leads to an impaired response to singlet oxygen signaling under light stress.
2014-04-21 | GSE49596 | GEO
Project description:We identified a small zinc finger protein, MBS, as a new mediator of singlet oxygen responses in Chlamydomonas and Arabidopsis. MBS is required for induction of singlet oxygen-dependent gene expression and, upon oxidative stress, accumulates in distinct granules in the cytosol of Arabidopsis cells. First, we recorded changes in light stress-regulated gene expression profiles after genetically perturbing MBS function by isolating mutants for the two MBS genes (MBS1 and MBS2) and by overexpression of MBS1 in Arabidopsis thaliana. Then, these light stress-related gene expression profiles were analyzed with respect to genes specifically responding to singlet oxygen and hydrogen peroxide/superoxide. The results indicated that MBS inactivation leads to an impaired response to singlet oxygen signaling under light stress. Knock-out or knock-down of the MBS1 and MBS2 genes and overexpression of MBS1 in Arabidopsis thaliana were compared with the wild type and the flu mutant as controls under light stress. Arabidopsis seedlings of mbs1-1, RNAi-MBS2/mbs1-1, 35S:MBS1, the wild type and the flu mutant were harvested at 0 h and 3 h of light stress (HL, 1000 µE m−2 s−1). Total RNA was extracted and cDNA was hybridized to Affymetrix ATH1 microarrays in three biological replicates.
2014-04-21 | E-GEOD-49596 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the following subset Series: GSE30645: Expression analysis of the singlet oxygen resistant 1 (sor1) mutant GSE30646: Response of Chlamydomonas reinhardtii to different oxidative and electrophilic stress conditions Refer to individual Series
2011-07-14 | E-GEOD-30648 | biostudies-arrayexpress
Project description:We used the flu mutant of Arabidopsis to detail gene expression in response to singlet oxygen. The conditional flu mutant of Arabidopsis accumulates excess protochlorophyllide in the dark within chloroplast membranes that upon illumination acts as a photosensitizer and generates singlet oxygen. Immediately after the release of singlet oxygen mature flu plants stop growing, whereas seedlings bleach and die. Within the first 30 min after the release of singlet oxygen rapid changes in nuclear gene expression occur. Distinct sets of genes were activated that were different from those induced by other reactive oxygen species, superoxide or hydrogen peroxide. Keywords: Time course
2008-03-18 | GSE10876 | GEO
Project description:Linear tetrapyrrole (bilin)-based phytochrome sensors optimize photosynthetic light capture by mediating massive gene reprogramming in land plants, yet surprisingly, many sequenced chlorophyte (green) algae lack phytochrome genes. Previous studies on the heme oxygenase (hmox1) mutant of Chlamydomonas reinhardtii suggest that bilin biosynthesis in plastids is needed for regulation of a limited nuclear gene network implicated in oxygen detoxification during dark to light transitions. The hmox1 mutant is unable to grow photoautotrophically and poorly acclimates to increased illumination even in the presence of acetate. Here we show that these phenotypes reflect the reduced accumulation of PSI reaction centers as well as a loss of PSI and PSII antennae complexes during photoacclimation. Phenotypically, the hmox1 mutant is similar to the chlorophyll biosynthesis mutants, gun4, crd1 and cth1. However, many of the hmox1 phenotypes can be rescued by the application of exogenous biliverdin IXα, the bilin product of HMOX1; this rescue is independent of photosynthesis but strongly dependent upon blue light. RNA-Seq comparisons of hmox1, 4A+ wild type and two genetically complemented lines also reveal that bilins restore regulation of a small network of photosynthesis-associated nuclear genes. These include genes responsible for chlorophyll biosynthesis (CHLI1/2), PSI light-harvesting (LHCA4) and naphthoquinone metabolism (MEN2), all of which show reduced photoinduction in the hmox1 mutant. We propose that a bilin-based, blue light sensory system is responsible for the maintenance of a functional photosynthetic apparatus in light-grown C. reinhardtii. This critical and possibly ancestral role for bilins may be responsible for retention of bilin biosynthesis in all eukaryotic photosynthetic species.
2019-01-24 | GSE77388 | GEO