Degradation of cellular miR-27 by a novel, highly abundant viral transcript is important for efficient virus replication in vivo.
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE34475 | GEO | 2012/03/01
SECONDARY ACCESSION(S): PRJNA151355
REPOSITORIES: GEO
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Project description:Cytomegaloviruses express large amounts of viral miRNAs during lytic infection, yet, they only modestly alter the cellular miRNA profile. The most prominent alteration upon lytic murine cytomegalovirus (MCMV) infection is the rapid degradation of the cellular miR-27a and miR-27b. Here, we report that this regulation is mediated by the <1.7 kb spliced and highly abundant MCMV m169 transcript. Specificity to miR-27a/b is mediated by a single, apparently optimized, miRNA binding site located in its 3'-UTR. This site is easily and efficiently retargeted to other cellular and viral miRNAs by target site replacement. Expression of the 3'-UTR of m169 by an adenoviral vector was sufficient to mediate its function, indicating that no other viral factors are essential in this process. Degradation of miR-27a/b was found to be accompanied by 3'-tailing and -trimming. Despite its dramatic effect on miRNA stability, we found this interaction to be mutual, indicating potential regulation of m169 by miR-27a/b. Most interestingly, three mutant viruses no longer able to target miR-27a/b, either due to miRNA target site disruption or target site replacement, showed significant attenuation in multiple organs as early as 4 days post infection, indicating that degradation of miR-27a/b is important for efficient MCMV replication in vivo. Small RNA sequencing from total RNA or Ago2 associated small RNAs extracted from mock- or MCMV-infected NIH-3T3 cells
2012-03-01 | E-GEOD-34475 | biostudies-arrayexpress
Project description:One goal of viral infection is to reprogram the host cell to optimize viral replication. As part of this process, viral miRNAs may compete for components of the miRNA/siRNA pathway as well as regulate cellular targets. Mouse Cytomegalovirus has been described to generate large numbers of viral miRNAs during lytic infection and was therefore used to analyze the impact of viral miRNAs on the host cell small RNA system as well as to check for sorting of viral small RNAs into specific Ago-proteins. Deep sequencing analysis of MCMV infected cells revealed that viral miRNAs represent only app. 13% of all detected miRNAs. All previously described MCMV miRNAs with the exception of miR-m88-1* were confirmed and for the MCMV miR-m01-1 hairpin an additional miRNA, designated miR-m01-1-3p, was found. Its presence was confirmed by qPCR and Northern Blot. Deep sequencing after RISC IP with antibodies specific for either Ago1 or Ago2 showed that all MCMV miRNAs are loaded into both RISC complexes. The ratio of MCMV to mouse miRNAs was not increased after immunoprecipitation of Ago-proteins. Viral miRNAs therefore do not overwhelm the host miRNA processing system nor are they preferentially incorporated into RISC. We found that 3 mouse miRNAs showed an altered expression due to MCMV infection. Down-regulation of miR-27a, as previously described, could be confirmed. In addition, miR-26a was down-regulated and an up-regulation of miR-7a dependent on viral protein expression could be observed. Examination of small RNA expression in uninfected vs. infected cells, immunoprecipitation + sequencing of Ago1 and Ago2 loaded small RNAs in infected cells
2012-06-30 | E-GEOD-36919 | biostudies-arrayexpress
Project description:One goal of viral infection is to reprogram the host cell to optimize viral replication. As part of this process, viral miRNAs may compete for components of the miRNA/siRNA pathway as well as regulate cellular targets. Mouse Cytomegalovirus has been described to generate large numbers of viral miRNAs during lytic infection and was therefore used to analyze the impact of viral miRNAs on the host cell small RNA system as well as to check for sorting of viral small RNAs into specific Ago-proteins. Deep sequencing analysis of MCMV infected cells revealed that viral miRNAs represent only app. 13% of all detected miRNAs. All previously described MCMV miRNAs with the exception of miR-m88-1* were confirmed and for the MCMV miR-m01-1 hairpin an additional miRNA, designated miR-m01-1-3p, was found. Its presence was confirmed by qPCR and Northern Blot. Deep sequencing after RISC IP with antibodies specific for either Ago1 or Ago2 showed that all MCMV miRNAs are loaded into both RISC complexes. The ratio of MCMV to mouse miRNAs was not increased after immunoprecipitation of Ago-proteins. Viral miRNAs therefore do not overwhelm the host miRNA processing system nor are they preferentially incorporated into RISC. We found that 3 mouse miRNAs showed an altered expression due to MCMV infection. Down-regulation of miR-27a, as previously described, could be confirmed. In addition, miR-26a was down-regulated and an up-regulation of miR-7a dependent on viral protein expression could be observed.
2012-07-01 | GSE36919 | GEO
Project description:Many microRNAs (miRNAs) exist alongside abundant miRNA isoforms (isomiRs), most of which arise from post-maturation sequence modifications, such as 3’ uridylation. However, the ways in which these sequence modifications affect miRNA function remain poorly understood. Here, using human miR-27a in cell lines as a model, we have discovered that a nonfunctional target site unable to base pair extensively with the miRNA seed sequence can regain function when an upstream adenosine is able to base-pair with a post-transcriptionally added uridine in the miR-27a tail. This Tail-U-Mediated Repression (TUMR) is abolished in cells lacking the uridylation enzymes TUT4 and TUT7, indicating that uridylation alters miRNA function by modulating target recognition. We identified a set of non-canonical targets in human cells that are specifically regulated by uridylated miR-27a. We provide evidence that TUMR expands the targets of other endogenous miRNAs. Our study reveals a function for uridylated isomiRs in regulating non-canonical miRNA targets.
2019-08-15 | GSE121327 | GEO
Project description:In infection with an adenovirus, it remains to be clarified whether host miRNAs affect Ad replication. We focused on miR-27 as an miRNA crucial for regulation of Ad infection because miR-27 has been reported to be involved in infection of other viruses, including MCMV and herpesvirus saimiri (HVS). We used microarrays to detail gene expression profiles in miR-27a/b-overexpressing HeLa cells and demonstarted that expression levels of various genes were down- or up-regulated following transfection with miR-27a/b mimics.
2017-04-03 | GSE85587 | GEO
Project description:The microRNA (miRNA) dependent regulation of gene expression confers robustness to cellular phenotypes and controls responses to extracellular stimuli. Although a single miRNA can regulate expression of hundreds of target genes, it is unclear whether any of its distinct biological functions can be due to the regulation of a single target. To explore in vivo the function of a single miRNA-mRNA interaction, we mutated the 3' UTR of a major miR-155 target SOCS1 to specifically disrupt its regulation by miR-155. We found that under physiologic conditions and during autoimmune inflammation or viral infection some immunological functions of miR-155 were fully or largely attributable to the regulation of SOCS1, whereas others could be accounted only partially or not at all by this interaction. Our data suggest that the role of a single miRNA-mRNA interaction is cell type- and biological context-dependent. Naive WT, SOCS1KI and miR-155KO OVA-specific OT-1 TCR transgenic CD8+ T cells (1x10e4 per mouse) were adoptively transferred into CD45.1+ wt mice prior to infection with MCMV-OVA. WT, SOCS1KI and miR-155KO NK cells (2x10e5 per mouse) were adoptively transferred into CD45.1+ Klra8KO (Ly49H-deficient) mice prior to infection with MCMV. On d4 post infection, CD45.2+ CD44+ CD8+ OT-1 and CD45.2+ Ly49H+ NK1.1+ CD3- NK cells were FACS-sorted (BD FACS ARIA2). Each condition has 3 sequencing replicates.
2015-05-10 | E-GEOD-68511 | biostudies-arrayexpress
Project description:Gene expression profiling was carried out in Huh-7.5 cells in which miR-27a was over- or under-expressed. Transfection of cells with pre-miR-27a and pre-miR-control, or anti-miR-27a and anti-miR-control enabled down- and up-regulated genes to be determined, respectively. Replication and infectivity of the lipotrophic hepatitis C virus (HCV) is regulated by cellular lipid status. Among differentially expressed micro (mi)RNAs, we found that miR-27a was preferentially expressed in HCV-infected compared with hepatitis B virus (HBV)-infected liver. Gene expression profiling of Huh-7.5 cells showed that miR-27a regulates lipid metabolism by targeting the lipid synthetic transcriptional factor, RXRα, and the lipid transporter, ABCA1 Carrying out a Target Scan (Release 5.2) of miR-27a predicted 921 candidate target genes, and functional gene ontology enrichment analysis of these genes by MetaCore (Thomson Reuters, NY) showed that miR-27a could target the signaling pathways of cytoskeleton remodeling and lipid metabolism . To examine whether these signaling pathways were regulated by miR-27a, gene expression profiling was carried out in Huh-7.5 cells in which miR-27a was over- or under-expressed. Transfection of cells with pre-miR-27a and pre-miR-control, or anti-miR-27a and anti-miR-control enabled down- and up-regulated genes to be determined, respectively. Huh-7.5 cells with miR-27a over- or under-expressed
2013-06-05 | E-GEOD-41737 | biostudies-arrayexpress
Project description:During viral infections cellular gene expression is subject to rapid alterations induced by both viral and antiviral mechanisms. In this study, we applied metabolic labeling of newly transcribed RNA with 4-thiouridine (4sU-tagging) to dissect the real-time kinetics of cellular and viral transcriptional activity during lytic murine cytomegalovirus (MCMV) infection. Microarray profiling on newly transcribed RNA obtained from different times during the first six hours of MCMV infection revealed discrete functional networks of cellular genes regulated with distinct kinetics at surprising temporal resolution. Most of these were undetectable in total RNA, either due to low temporal sensitivity of standard gene expression profiling using total RNA, or due to rapid (viral) counter-regulation. Furthermore, metabolic labeling and purification of newly transcribed RNA detailed the real-time kinetics and regulation of viral gene expression in absence of any interfering virion-associated RNA. Both qRT-PCR and next-generation sequencing of newly transcribed RNA demonstrated an unexpected peak of viral gene expression during the first two hours of infection including transcription of immediate early, early and even well characterized late genes. Interestingly, this peak was subject to rapid gene silencing (independent of the multiplicity of infection) with similar transcriptional activity only reached late in infection. For some genes, e.g. m152, this resulted in massive down-regulation of transcriptional activity by 6 hours post infection, which was not even reversed late in infection. Our findings thus highlight the importance of transcriptional activity during the first few hours of CMV infection and hint at novel mechanisms governing the kinetics of viral gene expression. In conclusion, studying real-time transcriptional activity during lytic CMV infection provides intriguing new insights into the regulation of cellular and viral gene expression. In total 13 samples were examined: 3 samples of total RNA (mock, 25, 48 hours past MCMV infection), 3 samples pre-existing RNA (mock, 25, 48 hpi), and 7 samples newly-transcribed RNA (mock, 1-2, 5-6, 11-12, 18-19, 24-25, 47-48 hpi)
2013-02-14 | E-GEOD-35833 | biostudies-arrayexpress
Project description:Expression data from NIH-3T3 cells left uninfected or infected with MCMV for 2, 4 or 6h on total RNA as well as newly transcribed RNA labeled for 1-2, 3-4, and 5-6hpi. For newly transcribed RNA, the isolated RNA was labeled for 1h and separated from total cellular RNA following Trizol RNA preparation and thiol-specific biotinylation. We used microarrays to analyze the effects of MCMV infection in total and newly transcribed RNA. During viral infections cellular gene expression is subject to rapid alterations induced by both viral and antiviral mechanisms. In this study, we applied metabolic labeling of newly transcribed RNA with 4-thiouridine (4sU-tagging) to dissect the real-time kinetics of cellular and viral transcriptional activity during lytic murine cytomegalovirus (MCMV) infection. Microarray profiling on newly transcribed RNA obtained from different times during the first six hours of MCMV infection revealed discrete functional networks of cellular genes regulated with distinct kinetics at surprising temporal resolution. Most of these were undetectable in total RNA, either due to low temporal sensitivity of standard gene expression profiling using total RNA, or due to rapid (viral) counter-regulation. Furthermore, metabolic labeling and purification of newly transcribed RNA detailed the real-time kinetics and regulation of viral gene expression in absence of any interfering virion-associated RNA. Both qRT-PCR and next-generation sequencing of newly transcribed RNA demonstrated an unexpected peak of viral gene expression during the first two hours of infection including transcription of immediate early, early and even well characterized late genes. Interestingly, this peak was subject to rapid gene silencing (independent of the multiplicity of infection) with similar transcriptional activity only reached late in infection. For some genes, e.g. m152, this resulted in massive down-regulation of transcriptional activity by 6 hours post infection, which was not even reversed late in infection. Our findings thus highlight the importance of transcriptional activity during the first few hours of CMV infection and hint at novel mechanisms governing the kinetics of viral gene expression. In conclusion, studying real-time transcriptional activity during lytic CMV infection provides intriguing new insights into the regulation of cellular and viral gene expression. NIH-3T3 cells (5th to 15th passage after thawing) were split from confluent plates 24h before start of the experiment. At the beginning of the experiment about 80% confluency was reached. The experiment was started by applying fresh, prewarmed, CO2-equilibrated medium containing either mock or MCMV particles (MOI 1). The MOI was increased by ~10-fold through centrifugal enhancement (2000g, 30min). Labeling was started 1, 3, or 5hpi after the end of centrifugal enhancement.
2013-02-01 | E-GEOD-35919 | biostudies-arrayexpress
Project description:Comparison af adherent growing breast cancer cell lines versus mammospheres under serum-free conditions Background: In patients with breast cancer, subsets of long-lived cells tolerate chemotherapies. These chemoresistant cells can remain dormant at secondary sites, such as bone and lung, for years and decades. Cancer cells endowed with drug resistance are maintained in vivo in a quiescent slow-growing state that preserves them from anti-proliferative cancer drugs. The mechanism of conversion from dormancy to growth remains poorly understood. We aimed to identify microRNAs (miRNAs) as master regulators of cancer stem cells (CSCs) maintainance, because one of the characteristics of CSCs is their slow proliferation or dormancy. MiRNA targeting CSCs may be an effective therapy to improve the prognosis of breast cancer patients. Methods: We performed miRNA array analysis to identify differences miRNA expression profiles between adherent cells and mammospheres that contain higher number of breast cancer stem cells (BCSCs). In this approach, we focused on expression of hsa-miR-27a. Further, roles of hsa-miR-27a target genes in maintaining BCSC properties were analysed . Results: Here, we showed that hsa-miR-27a was downregulated in mammosphere cells. The formation of BCSCs was attenuated by transfection of hsa-miR-27a. We found that hsa-miR-27a targets F-box and WD-40 domain protein 7 (FBW7), a tumor suppressor gene, thereby inducing tumor dormancy. Additionally, we found that hsa-miR-27a targets genes involved in GSH synthesis, including xCT (encoded by SLC7A11), a heterodimeric protein of a transporter subunit of the xC(-) system, cystathionine gamma-lyase (CTH/CSE), and nuclear factor-erythroid 2-related factor 2 (Nrf2/NFE2L2), thereby increasing intracellular reactive oxygen species (ROS) levels. Upregulation of these genes by antisense (as)-miR-27a induced autophagy. Conclusions: Previous studies showed that expression of hsa-miR-27a is elevated in breast cancer. Here, we showed that expression of hsa-miR-27a was reduced in BCSC. CSCs in the dormant state are resistant to chemotherapy due to inhibition of ROS accumulation in these cells. These results demonstrate that hsa-miR-27a plays an essential role in maintaining the BCSCs phenotype via regulation of FBW7, ROS related genes and the Nrf2 pathway, as well as in the dormant-to-proliferative switch of breast cancer cells. Thus, hsa-miR-27a represents a novel strategy for various type of breast cancer.
2019-03-06 | GSE127849 | GEO