Feedback regulation of RNase E during UV-stress response in cyanobacteria
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PROVIDER: PRJNA773405 | ENA |
REPOSITORIES: ENA
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Project description:Endoribonucleases govern the maturation and degradation of RNA and are indispensable in the post-transcriptional regulation of gene expression. A key endoribonuclease in many bacteria is RNase E. To ensure an appropriate supply of RNase E, some bacteria such as E. coli have evolved a tightly functioning feedback regulation of RNase E, which is mediated in cis by the rne 5′-untranslated region (5′UTR); however, the mechanisms involved in the control of RNase E in other bacteria have largely remained unknown. Cyanobacteria rely on solar light as energy source for their photosynthetic lifestyle, despite the inherent ultraviolet (UV) irradiation. Here, we revealed the global gene expression response in the cyanobacterium Synechocystis sp. PCC 6803 after exposure to UV light and discovered a unique response of RNase E: a rapidly increasing enzymatic activity although stability of the protein was lowered . In parallel, we observed a substantial stabilization of the full-length mRNA specifically after UV-C treatment, while the 5′UTR accumulated under all conditions. Mapping of RNA 3′ends and in vitro cleavage assays revealed that RNase E cleaves within a stretch of six consecutive uridine residues within the rne 5′UTR, indicating the autoregulation of RNase E via its own 5′UTR. These observations imply that RNase E in cyanobacteria evolved as a substantial contributor in re-shaping the transcriptome during the UV stress response, that its required activity level is maintained despite enhanced turnover of the protein, and that the underlying mechanism involves a feedback mechanism acting on a uridine-rich element within the rne 5′UTR.
2021-10-22 | GSE186330 | GEO
Project description:Zinc oxide (ZnO) nanoparticles are commonly used in sunscreens for their UV-filtering properties. Their growing use can lead to their release into ecosystems, raising question about their toxicity. Effects of these engineered nanomaterials (ENMs) on cyanobacteria, which are important primary producers involved in many biogeochemical cycles, are unknown. In this study, we investigated by several complementary approaches the toxicological effects of two marketed ZnO-ENMs (coated and uncoated) on the model cyanobacteria Synechococcus elongatus PCC 7942. It was shown that despite the rapid adsorption of ENMs on cell surface, toxicity is mainly due to labile Zn released by ENMs. Zn dissipates cell membrane potential necessary for both photosynthesis and respiration, and induces oxidative stress leading to lipid peroxidation and DNA damages. It leads to global downregulation of photosystems, oxidative phosphorylation, and transcription/translation machineries. This also translates into significant decrease of intracellular ATP content and cell growth inhibition. However, there is no major loss of pigments and even rather an increase in exposed cells compared to controls. A proposed way to reduce the environmental impact of Zn would be the improvement of the coating stability to prevent solubility of ZnO-ENMs.
2019-06-05 | GSE102914 | GEO
Project description:af09_lignin - dml6 - Transcriptome analysis of lignin mutants and UV stress effect on secondary wall synthesis - DML6 vs S DML6+UV vs S+UV S vs S+UV DML6 vs DML6+UV Keywords: normal vs disease comparison,treated vs untreated comparison
2007-06-20 | GSE8094 | GEO
Project description:RNase III is a ribonucleases that recognizes and cleaves double-stranded RNA. RNase III has been known be involved in rRNA processing, but has many additional roles controlling both expression and RNA turnover of specific messages. Many organisms have just one RNase III while some have both a full length RNase III and a mini-III that lacks the double-stranded RNA binding domain. The cyanobacteria Synechococcus sp. PCC 7002 has three homologs of RNase III that are unessential even when deleted in combination. We were interested what coding regions these RNase III enzymes were influencing and if they had redundant or distinct specificities. To address these questions we collected samples for RNA-sequencing from WT, the single, double, and triple RNase III mutants in triplicate. Approximately 20% of genes were differentially expressed in various mutants with some operons and regulons showing complex changes in expression levels between mutants. We describe the role of two RNase III’s in 23S rRNA maturation, and show how the third is involved in copy number regulation of one of the six plasmids (pAQ3). Purified enzymes were capable of cleaving some E. coli RNase III target sequences, highlighting the remarkably conserved substrate specificity between organisms yet complex regulation of gene expression.
2018-01-16 | GSE99279 | GEO
Project description:Differential expression of microRNAs was studied in maize leaves after an 8-h-exposure under UV-B light. As a control, plants were kept in the greenhouse in the absence of UV-B 4-week maize plants were grown in the greenhouse in the absence of UV-B. Then, they were divided in two groups. One group was treated with UV-B lights provided once for 8 h, starting 3 h after the beginning of the light period, using fixtures mounted 30 cm above the plants (Phillips, F40UVB 40 W and TL 20 W/12) at a UV-B intensity of 2 W m-2, UV-A: 0.65 W m-2. The bulbs were covered with cellulose acetate to exclude wavelengths <280 nm. For the second control group, plants were exposed for 8 h under the same lamps covered with polyester film (no UV-B treatment, UV-B: 0.04 W m-2, UV-A: 0.4 W m-2). Lamp output was recorded using a UV-B/UV-A radiometer (UV203 A+B radiometer, Macam Photometrics, Ltd, Livingston, UK) to insure that both the bulbs and filters provided the designated UV dosage in all treatments. Leaf samples were collected immediately after irradiation. RNA was extracted immediately after the treatments, and used for the microRNA microarray experiments.
2013-10-31 | E-GEOD-19768 | biostudies-arrayexpress
Project description:Plants respond to low levels of UV-B radiation with a coordinated photomorphogenic response that allows acclimation to this environmental stress factor. The key players in this UV-B response are COP1 (an E3 ubiquitin ligase), UVR8 (a ?-propeller protein), and HY5 (a bZIP transcription factor). We have shown previously that an elevated UV-B-specific response is associated with dwarf growth, indicating the importance of balancing UV-B-specific signaling. Negative regulators of this pathway are not known, however. Here, we describe two highly related WD40-repeat proteins, REPRESSOR OF UV-B PHOTOMORPHOGENESIS 1 (RUP1) and RUP2, that interact directly with UVR8 as potent repressors of UV-B signaling. Both genes were transcriptionally activated by UV-B in a COP1-, UVR8-, and HY5-dependent manner. rup1 rup2 double mutants showed an enhanced response to UV-B and elevated UV-B tolerance after acclimation. Overexpression of RUP2 resulted in reduced UV-B-induced photomorphogenesis and impaired acclimation, leading to hypersensitivity to UV-B stress. These results are consistent with an important regulatory role for RUP1 and RUP2, which act downstream of UVR8-COP1 in a negative feedback loop impinging on UVR8 function, balancing UV-B defense measures and plant growth.
| S-EPMC2993346 | biostudies-literature
Project description:Differential expression of microRNAs was studied in maize leaves after an 8-h-exposure under UV-B light. As a control, plants were kept in the greenhouse in the absence of UV-B
2013-10-31 | GSE19768 | GEO
Project description:Collection of cyanobacteria at NWU, South Africa
| PRJNA680469 | ENA