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Drosha knockdown in human cells reduces viability but does not affect snRNA or rRNA synthesis or processing

ABSTRACT: 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

ORGANISM(S): Homo sapiens

PROVIDER: GSE6767 | GEO | 2008/01/01

SECONDARY ACCESSION(S): PRJNA98941

REPOSITORIES: GEO

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RNAi of human cells after Drosha knockdown reduces viability but does not affect snRNA or rRNA synthesis or processing

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

RNAi of human HeLa cells knocked down for Drosha or DGCR8

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

Drosha or DGCR8 knockdown effects on mRNA levels in HeLa

2009-02-05 | GSE13639 | GEO

Transcriptome analysis of the Rhodobacter sphaeroides RNase III mutant (inactivated enzyme) by total RNA sequencing

Project description:RNase III is an important and highly conserved endoribonuclease known to impact rRNA, mRNA and ncRNA abundances by RNA processing. In this study we analyzed the effects of an inactivation of RNase III (inactivated through substitution of two strictly conserved amino acids within the active enzyme center) on the transcriptome of the facultative phototrophic model organism Rhodobacter sphaeroides.

2024-02-19 | GSE236804 | GEO

Function of three homologs of RNase III in Synechococcus sp. PCC 7002

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.

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Transcription profiling of E. coli mutants lacking the rne gene and over expressing Rng

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2005-07-11 | E-SMDB-1515 | biostudies-arrayexpress

RNase G complementation of rne null mutation identifies functional interrelationships with RNase E

2005-08-13 | E-GEOD-3123 | biostudies-arrayexpress

Single cut products of Microprocessor on pri-miRNAs

Project description:The human Microprocessor complex cleaves primary microRNA (miRNA) transcripts (pri-miRNAs) to initiate miRNA synthesis. Microprocessor consists of DROSHA (an RNase III enzyme), and DGCR8. DROSHA has two conserved RNase III domains, which make double cuts on each of pri-miRNA strands. In this study, we show that Microprocessor has an unexpected single-cut activity, which creates a single cut on just one of the pri-miRNA strands using one of the two RNase III domains of DROSHA. This cleavage does not lead to the production of miRNA but instead it downregulates miRNA expression. We also demonstrate that certain RNA elements facilitate the single-cut activity of Microprocessor, and by manipulating these elements, we can regulate the ratio of single-cut to double-cut activities, thus controlling miRNA production both in vitro and in vivo.

2020-01-24 | GSE138950 | GEO

Homo sapiens

Project description:Drosha knockdown in human cells reduces viability but does not affect snRNA or rRNA synthesis or processing

| PRJNA98941 | ENA

Mapping of internal monophosphate 5’ ends of Bacillus subtilis messenger RNAs and ribosomal RNAs in wild-type and ribonuclease-mutant strains

Project description:The narrow-specificity endoribonuclease RNase III and the 5’ exonuclease RNase J1 have been recently found to be not essential in the Gram-positive model organism, Bacillus subtilis. In this study, we performed a global analysis of internal 5’ ends that are generated or acted upon by these enzymes. An RNA-Seq protocol known as PARE (Parallel Analysis of RNA Ends) was used to capture 5’ monophosphorylated RNA ends in ribonuclease wild-type and mutant strains. Comparison of PARE peaks in strains with RNase III present or absent showed that, in addition to its well-known role in ribosomal (rRNA) processing, many coding sequences and intergenic regions were direct targets of RNase III. A set of regular RNA-seq experiments were performed to investigate RNA profiles in these strains and used to account for the changes in RNA abundance indirectly caused by the loss of RNase III in PARE. The PARE analysis also revealed an accumulation of 3’-proximal peaks that correlated with the absence of RNase J1, confirming the importance of RNase J1 in degrading RNA fragments that contain the transcription terminator structure. In addition, an endonuclease cleavage just two nucleotides downstream of the 16S rRNA 3’ end was discovered with PARE analysis. This latter observation begins to answer, at least for B. subtilis, a long-standing question on the exonucleolytic vs. endonucleolytic nature of 16S rRNA maturation

2016-01-27 | GSE77217 | GEO

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