Open Ocean and Coastal Strains of Marine Synechococcus display distinctly different Global Responses to DNA Damaging Agents
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PROVIDER: PRJNA171763 | ENA |
REPOSITORIES: ENA
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Project description:We have looked at the transcriptional response of well characterised Synechococcus open ocean (WH8102) and coastal (CC9311) isolates to two DNA damaging agents, mitomycin C and ethidium bromide, using whole genome expression microarrays. The coastal strain, which was able to grow on higher concentrations of both chemicals, showed differential regulation of a larger proportion of its genome following ‘toxic shock’ treatment with each agent. Many of the orthologous genes in these strains, including those encoding sensor kinases, showed different transcriptional responses, with the CC9311 genes more likely to show significant changes for each tested treatment. While the overall response of each strain was considerably different, there were distinct transcriptional responses common to both strains observed for each DNA damaging agent, linked to the mode of action of each chemical. In both CC9311 and WH8102 there was evidence of SOS response induction under mitomycin C treatment, with genes encoding recA, the lexA repressor and umuC significantly upregulated in this experiment but not under ethidium bromide treatment. Conversely, ethidium bromide treatment tended to result in upregulation of the DNA-directed RNA polymerase genes, not observed following mitomycin C treatment. Interestingly, a large number of genes residing on putative genomic island regions of each genome also showed significant upregulation under one or both chemical treatments.
2013-08-01 | GSE39818 | GEO
Project description:We have looked at the transcriptional response of well characterised Synechococcus open ocean (WH8102) and coastal (CC9311) isolates to two DNA damaging agents, mitomycin C and ethidium bromide, using whole genome expression microarrays. The coastal strain, which was able to grow on higher concentrations of both chemicals, showed differential regulation of a larger proportion of its genome following M-bM-^@M-^Xtoxic shockM-bM-^@M-^Y treatment with each agent. Many of the orthologous genes in these strains, including those encoding sensor kinases, showed different transcriptional responses, with the CC9311 genes more likely to show significant changes for each tested treatment. While the overall response of each strain was considerably different, there were distinct transcriptional responses common to both strains observed for each DNA damaging agent, linked to the mode of action of each chemical. In both CC9311 and WH8102 there was evidence of SOS response induction under mitomycin C treatment, with genes encoding recA, the lexA repressor and umuC significantly upregulated in this experiment but not under ethidium bromide treatment. Conversely, ethidium bromide treatment tended to result in upregulation of the DNA-directed RNA polymerase genes, not observed following mitomycin C treatment. Interestingly, a large number of genes residing on putative genomic island regions of each genome also showed significant upregulation under one or both chemical treatments. In this series four conditions have been analyzed. These are 2 hour incubations (shock treatment) with ethidium bromide (EB, final conc 2ug/mL) and mitomycin C (MC, final conc 0.5 ug/mL) for Synechococcus sp. WH8102 and CC9311. For each slide, an experimental RNA sample was labeled with Cy3 or Cy5 and was hybridized with a reference RNA from a control sample (no addition of chemical agent) labeled with the other Cy dye. There are six slides per condition, each with at least two biological replicates and three technical replicates, including at least one flip-dye comparison. Each slide contains six replicate spots per gene.
2013-08-01 | E-GEOD-39818 | biostudies-arrayexpress
Project description:Chemotherapy Treatment alone with DNA damaging drugs might be as effective as chemotherapy combined with surgery in colorectal cancer (CRC) avoiding surgery complications.
| 2114543 | ecrin-mdr-crc
Project description:We have investigated whether gene expression signatures can be used to predict inter-individual responses to DNA damaging agents We used microarrays to detail inter-individual variation in gene expression across a healthy population under basal and damage induced conditions Keywords: dose (MNNG)
2008-09-23 | GSE10313 | GEO
Project description:Marine cyanobacteria are thought to be the most sensitive of the phytoplankton groups to copper toxicity, yet little is known of the transcriptional response of marine Synechococcus to copper shock. Global transcriptional response to two levels of copper shock was assayed in both a coastal and an open ocean strain of marine Synechococcus using whole genome expression microarrays. Both strains showed an osmoregulatory-like response, perhaps as a result of increasing membrane permeability. This could have implications for marine carbon cycling if copper shock leads to dissolved organic carbon leakage in Synechococcus. The two strains additionally showed a reduction in photosynthetic gene transcripts. Contrastingly, the open ocean strain showed a typical stress response whereas the coastal strain exhibited a more specific oxidative or heavy metal type response. In addition, the coastal strain activated more regulatory elements and transporters, many of which are not conserved in other marine Synechococcus strains and may have been acquired by horizontal gene transfer. Thus, tolerance to copper shock in some marine Synechococcus may in part be a result of an increased ability to sense and respond in a more specialized manner.
2009-07-01 | GSE13910 | GEO
Project description:Although N2 fixation can occur in free-living cyanobacteria, the unicellular endosymbiotic cyanobacterium Candidatus Atelocyanobacterium thalassa (UCYN-A) is considered to be a dominant N2-fixing species in marine ecosystems. Four UCYN-A sublineages are known from partial nitrogenase (nifH) gene sequences. However, few studies have investigated their habitat preferences and regulation by their respective hosts in open-ocean versus coastal environments. Here, we compared UCYN-A transcriptomes from oligotrophic open-ocean versus nutrient-rich coastal waters. UCYN-A1 metabolism was more impacted by habitat changes than UCYN-A2. However, across habitats and sublineages genes for nitrogen fixation and energy production were highly transcribed. Curiously these genes, critical to the symbiosis for the exchange of fixed nitrogen for fixed carbon, maintained the same schedule of diel expression across habitats and UCYN-A sublineages, including UCYN-A3 in the open-ocean transcriptomes. Our results undersore the importance of nitrogen fixation in UCYN-A symbioses across habitats, with consequences for community interaction and global biogeochemical cycles.
2023-02-23 | GSE206403 | GEO
Project description:Marine cyanobacteria are thought to be the most sensitive of the phytoplankton groups to copper toxicity, yet little is known of the transcriptional response of marine Synechococcus to copper shock. Global transcriptional response to two levels of copper shock was assayed in both a coastal and an open ocean strain of marine Synechococcus using whole genome expression microarrays. Both strains showed an osmoregulatory-like response, perhaps as a result of increasing membrane permeability. This could have implications for marine carbon cycling if copper shock leads to dissolved organic carbon leakage in Synechococcus. The two strains additionally showed a reduction in photosynthetic gene transcripts. Contrastingly, the open ocean strain showed a typical stress response whereas the coastal strain exhibited a more specific oxidative or heavy metal type response. In addition, the coastal strain activated more regulatory elements and transporters, many of which are not conserved in other marine Synechococcus strains and may have been acquired by horizontal gene transfer. Thus, tolerance to copper shock in some marine Synechococcus may in part be a result of an increased ability to sense and respond in a more specialized manner. In this series four conditions have been analyzed. These are moderate copper shock for Synechococcus sp. WH8102 and CC9311 (pCu 11.1 and pCu 10.1, respectively), and high copper shock for WH8102 and CC9311 (pCu 10.1 and pCu 9.1, respectively). For each slide, an experimental RNA sample was labeled with Cy3 or Cy5 and was hybridized with a reference RNA from a non-copper-shocked sample labeled with the other Cy dye. There are six or eight slides per condition, each with two biological replicates. There are three or four technical replicates for each biological replicate including at least one flip-dye comparison. Each slide contains six replicate spots per gene.
2010-05-17 | E-GEOD-13910 | biostudies-arrayexpress
Project description:Multiple RNA processing events including transcription, mRNA splicing and export are delicately coordinated by the TREX complex. As one of the essential subunits, DDX39B couples the splicing and export machineries by recruiting ALYREF onto mRNA. In this study, we further explore the functions of DDX39B in handling damaged DNA, and unexpectedly find that DDX39B facilitates DNA repair by homologous recombination through upregulating BRCA1. Specifically, DDX39B binds to and stabilizes BRCA1 mRNA. DDX39B ensures ssDNA formation and RAD51 accumulation at DSB sites by maintaining BRCA1 levels. Without DDX39B being present, ovarian cancer cells exhibit hypersensitivity to DNA-damaging chemotherapeutic agents like platinum or PARPi. Moreover, DDX39B-deficient mice show embryonic lethality or developmental retardation, highly reminiscent of those lacking BRCA1. High DDX39B expression is correlated with worse survival in ovarian cancer patients. Thus, DDX39B suppression represents a rational approach for enhancing the efficacy of chemotherapy in BRCA1-proficient ovarian cancers.
2020-08-21 | GSE156543 | GEO
Project description:Decades of research on marine N2 fixation focused on Trichodesmium, which are generally free-living cyanobacteria, but in recent years the endosymbiotic cyanobacterium Candidatus Atelocyanobacterium thalassa (UCYN-A) has received increasing attention. However, few studies have shed light on the influence of the host versus the habitat on UCYN-A N2 fixation and overall metabolism. Here we compared transcriptomes from natural populations of UCYN-A from oligotrophic open-ocean versus nutrient-rich coastal waters, using a microarray that targets the full genomes of UCYN-A1 and UCYN-A2 and known genes for UCYN-A3. We found that UCYN-A2, usually regarded as adapted to coastal environments, was transcriptionally very active in the open ocean and appeared to be less impacted by habitat change than UCYN-A1. Moreover, for genes with 24 h periodic expression we observed strong but inverse correlations among UCYN-A1, A2, and A3 to oxygen and chlorophyll, which suggests distinct host-symbiont relationships. Across habitats and sublineages, genes for N2 fixation and energy production had high transcript levels, and, intriguingly, were among the minority of genes that kept the same schedule of diel expression. This might indicate different regulatory mechanisms for genes that are critical to the symbiosis for the exchange of nitrogen for carbon from the host. Our results underscore the importance of N2 fixation in UCYN-A symbioses across habitats, with consequences for community interactions and global biogeochemical cycles.
| S-EPMC10153697 | biostudies-literature
Project description:Epithelial ovarian cancer (EOC) is very sensitive to upfront chemotherapy. This condition is attributable to defects in the DNA damage repair system. Agents that damage DNA are the main drugs used for its treatment. Many EOC cells have DNA repair deficiencies that confer susceptibility to these agents. Platinum is the most important agent for first-line and also for relapses, together with other drugs that can be given as monotherapy or along with platinum or other drugs. Lately, the emerging role of PARP inhibitors has changed the landscape of opportunities for patients with EOC. All these strategies will be reviewed in this article.
| S-EPMC7573464 | biostudies-literature