Homo sapiens
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ABSTRACT:
PROVIDER: PRJNA98941 | ENA |
REPOSITORIES: ENA
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Project description:We asked whether the human drosha protein, an RNase III homolog known to process microRNAs (miRNAs), might also be a small nuclear RNA (snRNA) 3' processing factor. Using retroviral siRNA silencing constructs, we stably knocked down drosha protein to nearly undetectable levels. Knockdown cells exhibited reduced growth rates and viability compared to controls, but no accumulation of unprocessed U2 snRNA precursors. In fungi, RNase III homologs process rRNA precursors and certain mRNAs. Although rRNA processing appears to be normal in the drosha knockdown cells, expression microarray analysis revealed misregulation of several mRNAs involved in cell growth and proliferation. Curiously, drosha knockdown appeared to downregulate the predicted mRNA targets of several miRNAs Keywords: siRNA knockdown
2008-01-01 | GSE6767 | GEO
Project description:We asked whether the human drosha protein, an RNase III homolog known to process microRNAs (miRNAs), might also be a small nuclear RNA (snRNA) 3' processing factor. Using retroviral siRNA silencing constructs, we stably knocked down drosha protein to nearly undetectable levels. Knockdown cells exhibited reduced growth rates and viability compared to controls, but no accumulation of unprocessed U2 snRNA precursors. In fungi, RNase III homologs process rRNA precursors and certain mRNAs. Although rRNA processing appears to be normal in the drosha knockdown cells, expression microarray analysis revealed misregulation of several mRNAs involved in cell growth and proliferation. Curiously, drosha knockdown appeared to downregulate the predicted mRNA targets of several miRNAs Experiment Overall Design: The experimental goal was to evaluate gene expression changes induced by siRNA knockdown of drosha. Four samples of HeLa cells were transfected with retroviral siRNA expression vectors: two replicates of an anti-GFP siRNA vector (siGFP) and two different anti-drosha siRNA vectors (sidroshaB and sidroshaC). Cells were selected with puromycin 24 hours after transfection and harvested 72 hours after transfection. Trizol-harvested RNA was processed with standard Affymetrix protocols and hybridized to U133Plus2.0 GeneChips. Signals were scaled to an arbitrary global mean value of 800.
2008-06-15 | E-GEOD-6767 | biostudies-arrayexpress
Project description:RNAi-mediated knockdown of DICER1 and DROSHA, enzymes critically involved in miRNA biogenesis, has been postulated to affect the homeostasis and the angiogenic capacity of human endothelial cells. To re-evaluate this issue, we reduced the expression of DICER1 or DROSHA by RNAi-mediated knockdown and subsequently investigated the effect of these interventions on the angiogenic capacity of human umbilical vein endothelial cells (HUVEC) in vitro (proliferation, migration, tube formation, endothelial cell spheroid sprouting) and in a HUVEC xenograft assay in immune incompetent NSGTM mice in vivo. In contrast to previous reports, neither knockdown of DICER1 nor knockdown of DROSHA profoundly affected migration or tube formation of HUVEC or the angiogenic capacity of HUVEC in vivo. Furthermore, knockdown of DICER1 and the combined knockdown of DICER1 and DROSHA tended to increase VEGF-induced BrdU incorporation and induced angiogenic sprouting from HUVEC spheroids. Consistent with these observations, global proteomic analyses showed that knockdown of DICER1 or DROSHA only moderately altered HUVEC protein expression profiles but additively reduced, for example, expression of the angiogenesis inhibitor thrombospondin-1. In conclusion, global reduction of miRNA biogenesis by knockdown of DICER1 or DROSHA does not inhibit the angiogenic capacity of HUVEC. Further studies are therefore needed to elucidate the influence of these enzymes in the context of human endothelial cell-related angiogenesis.
2022-02-17 | PXD027923 | Pride
Project description:SIRT7 is an NAD+-dependent protein deacetylase with important roles in ribosome biogenesis and cell proliferation. Previous studies have established that SIRT7 is associated with RNA polymerase I, interacts with pre-rRNA and promotes rRNA synthesis. Here we show that SIRT7 is also associated with snoRNAs that are involved in pre-rRNA processing and rRNA maturation. Knockdown of SIRT7 impairs U3 snoRNA-dependent early cleavage steps that are necessary for generation of 18S rRNA. Mechanistically, SIRT7 deacetylates U3-55k, a core component of the U3 snoRNP complex, and reversible acetylation of U3-55k modulates the association of U3-55k with U3 snoRNA. Deacetylation by SIRT7 enhances U3-55k binding to U3 snoRNA, which is a prerequisite for pre-rRNA processing. Under stress conditions, SIRT7 is released from nucleoli, leading to hyperacetylation of U3-55k and attenuation of prerRNA processing. The results reveal a multifaceted role of SIRT7 in ribosome biogenesis, regulating both transcription and processing of rRNA. CLIP-seq was performed in Flag-SIRT7-293T cells.
2016-01-07 | E-GEOD-76578 | biostudies-arrayexpress
Project description:Anaysis of mRNA changes in HeLa cells following knockdown of Drosha or DGCR8. Drosha is a nuclear RNase III that carries out microRNA (miRNA) processing by cleaving primary microRNA transcript (pri-miRNA). DGCR8 is an essential co-factor of Drosha. Keywords: gene expression array-based (RNA / in situ oligonucleotide)
2009-02-05 | GSE13639 | GEO
Project description:Anaysis of mRNA changes in HeLa cells following knockdown of Drosha or DGCR8. Drosha is a nuclear RNase III that carries out microRNA (miRNA) processing by cleaving primary microRNA transcript (pri-miRNA). DGCR8 is an essential co-factor of Drosha. Experiment Overall Design: siRNA against Drosha or DGCR8 were trasnfected into HeLa cells. siRNA against GFP was used as a control. Biologically duplicated total RNAs were prepared from HeLa cells, 24 hrs and 48 hrs after siRNA transfection.
2009-02-21 | E-GEOD-13639 | biostudies-arrayexpress
Project description:Maturation of canonical microRNA (miRNA) is initiated by DROSHA that cleaves the primary transcript (pri-miRNA). Over 1,800 miRNA loci are annotated in humans, but it remains largely unknown if and at which sites the pri-miRNAs are cleaved by DROSHA. Here we performed in vitro processing on a full set of human pri-miRNAs (miRBase v21) followed by sequencing. This comprehensive profiling enabled us to classify miRNAs based on DROSHA-dependence and map their cleavage sites with respective processing efficiency measures. Only 758 pri-miRNAs are confidently processed by DROSHA, while the majority may be non-canonical or false entries. Analyses of the DROSHA-dependent pri-miRNAs show key cis-elements for processing. We observe widespread alternative processing as well as unproductive cleavage events such as “nick” or “inverse” processing. SRSF3 is a broad-acting auxiliary factor modulating alternative processing and suppressing unproductive processing. The profiling data and methods developed in this study will allow systematic analyses of miRNA regulation.
2021-07-28 | PXD025767 | Pride
Project description:SIRT7 is an NAD+-dependent protein deacetylase with important roles in ribosome biogenesis and cell proliferation. Previous studies have established that SIRT7 is associated with RNA polymerase I, interacts with pre-rRNA and promotes rRNA synthesis. Here we show that SIRT7 is also associated with snoRNAs that are involved in pre-rRNA processing and rRNA maturation. Knockdown of SIRT7 impairs U3 snoRNA-dependent early cleavage steps that are necessary for generation of 18S rRNA. Mechanistically, SIRT7 deacetylates U3-55k, a core component of the U3 snoRNP complex, and reversible acetylation of U3-55k modulates the association of U3-55k with U3 snoRNA. Deacetylation by SIRT7 enhances U3-55k binding to U3 snoRNA, which is a prerequisite for pre-rRNA processing. Under stress conditions, SIRT7 is released from nucleoli, leading to hyperacetylation of U3-55k and attenuation of prerRNA processing. The results reveal a multifaceted role of SIRT7 in ribosome biogenesis, regulating both transcription and processing of rRNA.
2016-01-07 | GSE76578 | GEO
Project description:In all domains of life, the rate of protein synthesis is directly linked to the rates of cell growth and proliferation. Consequently, highly proliferative cancer cells are especially sensitive to perturbations in ribosome biogenesis. While ribosome synthesis and cancer have a well-established relationship, only recently has ribosome biogenesis drawn interest as a cancer therapeutic target. Here, we have exploited the relationship between ribosome biogenesis and cancer cell proliferation by using a potent ribosome biogenesis inhibitor: RBI2 (Ribosome Biogenesis Inhibitor 2) to perturb cancer cell growth and viability. We demonstrate that RBI2 significantly decreases cell viability in malignant melanoma cells and breast cancer cell lines. Treatment with RBI2 dramatically and rapidly decreases ribosomal RNA (rRNA) synthesis, without affecting the occupancy of RNA polymerase I (Pol I) on the ribosomal DNA template. Next-generation RNA sequencing (RNA-seq) reveals that RBI2 and previously described ribosome biogenesis inhibitor CX-5461 induce distinct changes in the transcriptome. Investigation of the content of the pre-rRNAs through RT-qPCR reveals an increase in polyadenylation of cellular rRNA after treatment with RBI2, a known pathway by which rRNA degradation occurs. Northern blotting revealed that RBI2 does not appear to impair or alter rRNA processing. Collectively, these data suggest that RBI2 inhibits rRNA synthesis distinctly from other previously described ribosome biogenesis inhibitors, potentially through a novel pathway that upregulates turnover of premature rRNAs.
2021-11-08 | GSE188262 | GEO
Project description:Mutations in the human RMRP gene cause Cartilage Hair Hypoplasia (CHH), an autosomal recessive disorder characterized by skeletal abnormalities and impaired T-cell activation. RMRP encodes a non-coding RNA, which forms the core of the RNase MRP ribonucleoprotein complex. In budding yeast, RMRP cleaves a specific site in the pre-ribosomal RNA (pre-rRNA) during ribosome synthesis. CRISPR-mediated disruption of RMRP in human cells lines caused growth arrest, with pre-rRNA accumulation. Here, we analyzed disease-relevant primary cells, showing that mutations in RMRP impair mouse T cell activation and delay pre-rRNA processing. Analysis of pre-rRNA processing in patient-derived human fibroblasts with CHH-linked mutations showed a similar pattern of processing delay. Human cells engineered with the most common CHH mutation (70AG in RMRP) show specifically impaired pre-rRNA processing, resulting in reduced mature rRNA and a reduced ratio of cytosolic to mitochondrial ribosomes. Moreover, the 70AG mutation caused a reduction in intact RNase MRP complexes. Together, these results indicate that CHH is a ribosomopathy, and the first human disorder of rRNA processing to be described.
2021-12-14 | GSE190787 | GEO