Decoding the occupancy of RNA polymerase I on rDNA
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE242318 | GEO | 2024/09/10
REPOSITORIES: GEO
Similar Datasets
Project description:Following radiation damage, cells resume ribosome biogenesis for survival. We combined chromatin immunoprecipitation (ChIP) with mass spectrometry to identify key binding partners of RPA194 (the major subunit of RNA polI) at the rDNA loci in response to irradiation.
2023-07-20 | PXD041472 | Pride
Project description:PARP inhibitors (PARPi) are thought to control cancer cell growth by inducing synthetic lethality with DNA repair defects (e.g., in BRCA1/2 mutant cells). We have identified an alternate pathway for PARPi-mediated growth control in BRCA1/2-intact breast cancer cells involving rDNA transcription and ribosome biogenesis. PARP-1 binds to snoRNAs, which stimulate PARP-1 catalytic activity in the nucleolus independent of DNA damage. Activated PARP-1 ADPribosylates DDX21, an RNA helicase that localizes to the rDNA locus and promotes rDNA transcription when ADP-ribosylated. Treatment with PARPi or mutation of the ADP-ribosylation sites on DDX21 causes a reduction in rDNA transcription, as well as a reduction in ribosome biogenesis, protein translation, and cell growth. Our studies provide mechanistic insights into PARP-1-dependent ADP-ribosylation of DDX21 and its role in ribosome biogenesis. This pathway can be targeted for disruption in cancer cells that lack defects in DNA repair, but exhibit growth inhibition in response to PARPi.
2019-07-31 | GSE115761 | GEO
Project description:PARP inhibitors (PARPi) are thought to control cancer cell growth by inducing synthetic lethality with DNA repair defects (e.g., in BRCA1/2 mutant cells). We have identified an alternate pathway for PARPi-mediated growth control in BRCA1/2-intact breast cancer cells involving rDNA transcription and ribosome biogenesis. PARP-1 binds to snoRNAs, which stimulate PARP-1 catalytic activity in the nucleolus independent of DNA damage. Activated PARP-1 ADPribosylates DDX21, an RNA helicase that localizes to the rDNA locus and promotes rDNA transcription when ADP-ribosylated. Treatment with PARPi or mutation of the ADP-ribosylation sites on DDX21 causes a reduction in rDNA transcription, as well as a reduction in ribosome biogenesis, protein translation, and cell growth. Our studies provide mechanistic insights into PARP-1-dependent ADP-ribosylation of DDX21 and its role in ribosome biogenesis. This pathway can be targeted for disruption in cancer cells that lack defects in DNA repair, but exhibit growth inhibition in response to PARPi.
2019-07-31 | GSE115759 | GEO
Project description:Ribosomal RNAs (rRNAs) are essential components of the ribosome and are among the most abundant macromolecules in the cell. To ensure high rRNA level, eukaryotic genomes contain dozens to hundreds of rDNA genes, however, only a fraction of the rRNA genes seems to be active, while others are transcriptionally silent. In Drosophila rDNA units damaged by insertions of retrotransposons are repressed by an unknown mechanism. Here, we established a new model to study regulation of rDNA expression using molecularly marked rDNA transgenes. Using this model, we show that insertion of any heterologous sequence into rDNA leads to transcriptional repression. We found that SUMO (Small Ubiquitin-like Modifier) is required for efficient repression of damaged rDNA units. Surprisingly, SUMO also controls expression of intact rDNA, demonstrating that a single pathway is responsible for both selective repression of damaged units and silencing of surplus rDNA.
2020-02-01 | GSE141068 | GEO
Project description:PARP inhibitors (PARPi) prevent cancer cell growth by inducing synthetic lethality with DNA repair defects (e.g., in BRCA1/2 mutant cells). We have identified an alternate pathway for PARPi-mediated growth control in BRCA1/2-intact breast cancer cells involving rDNA transcription and ribosome biogenesis. PARP-1 binds to snoRNAs, which stimulate PARP-1 catalytic activity in the nucleolus independent of DNA damage. Activated PARP-1 ADP-ribosylates DDX21, an RNA helicase that localizes to nucleoli and promotes rDNA transcription when ADP-ribosylated. Treatment with PARPi or mutation of the ADP-ribosylation sites reduce DDX21 nucleolar localization, rDNA transcription, ribosome biogenesis, protein translation, and cell growth. The salient features of this pathway are evident in xenografts in mice and human breast cancer patient samples. Elevated levels of PARP-1 and nucleolar DDX21 are associated with cancer-related outcomes. Our studies provide a mechanistic rationale for efficacy of PARPi in cancer cells lacking defects in DNA repair whose growth is inhibited by PARPi.
2019-07-31 | GSE115760 | GEO
Project description:To sustain growth, budding yeast actively transcribes its ribosomal gene array (rDNA) in the nucoleolus to produce ribosomes and proteins. However, intense transcription during rDNA replication may provoke collisions between RNA polymerase I (Pol I) and the replisome, may cause replication fork instability, double-strand breaks, local recombinations and rDNA instability. The latter is manifested by rDNA array expansion or reduction and the formation of extrachromosomal rDNA circles, anomalies that accelerate aging in yeast. Transcription also interferes with the resolution, condensation and segregation of the sister chromatid rDNA arrays. As a consequence, rDNA segregation lags behind the rest of the yeast genome and occurs in late anaphase when rDNA transcription is temporarily shut off. How yeast promotes the stability and transmission of its rDNA array while satisfying a constant need for ribosomes remains unclear. Here we show that the downregulation of Pol I by the conserved cell cycle kinase Rio1 spatiotemporally coordinates rDNA transcription, replication and segregation. More specifically, Rio1 activity promotes copy-number stability of the replicating rDNA array by curtailing Pol I activity and by localising the histone deacetylase Sir2, which establishes a heterochromatic state that silences rDNA transcription. At anaphase entry, Rio1 and the Cdc14 phosphatase target Pol I subunit Rpa43 to dissociate Pol I from the 35S rDNA promoter. The rDNA locus then condensates and segregates, thereby concluding the genome transmission process. Rio1 is involved in ribosome maturation in the cytoplasm of budding yeast and human cells. Additional engagements in the cytoplasm or roles in the nucleus are unknown. Our study describes its first nuclear engagement as a Pol I silencing kinase. This activity may prove highly relevant as dysregulated RNA polymerase I activity has been associated with cancer initiation and proliferation.
2017-02-10 | GSE54930 | GEO
Project description:4C procedure was used for analysis of genomic contacts of rDNA units in HEK 293T cells. The primers for 4C were selected inside IGS. Our data indicate that mostly rDNA units exhibit close proximity with pericentromeric regions in different chromosomes. We also detected the contacts within a rDNA unit and between rDNA units. Examination of rDNA genome-wide contacts in HEK 293T cells using 4C approach.
2014-10-04 | E-GEOD-49193 | biostudies-arrayexpress
Project description:The role of ribosome biogenesis in erythroid development is supported by the recognition of erythroid defects in ribosomopathies in both Diamond-Blackfan anemia and 5q- syndrome. Whether ribosome biogenesis exerts a regulatory function on normal erythroid development is still unknown. In the present study, a detailed characterization of ribosome biogenesis dynamics during human and murine erythropoiesis shows that ribosome biogenesis is abruptly interrupted by the drop of rDNA transcription and the collapse of ribosomal protein neo-synthesis. Its premature arrest by RNA polI inhibitor, CX-5461 targets the proliferation of immature erythroblasts. We also show that p53 is activated spontaneously or in response to CX-5461 concomitantly to ribosome biogenesis arrest, and drives a transcriptional program in which genes involved in cell cycle arrest, negative regulation of apoptosis and DNA damage response were upregulated. RNA polI transcriptional stress results in nucleolar disruption and activation of ATR-CHK1-p53 pathway. Our results imply that the timing of ribosome biogenesis extinction and p53 activation are crucial for erythroid development. In ribosomopathies in which ribosome availability is altered by unbalanced production of ribosomal proteins, the threshold of ribosome biogenesis down-regulation could be prematurely reached and together with pathological p53 activation prevents a normal expansion of erythroid progenitors.
2020-09-14 | GSE157208 | GEO
Project description:The role of ribosome biogenesis in erythroid development is supported by the recognition of erythroid defects in ribosomopathies in both Diamond-Blackfan anemia and 5q- syndrome. Whether ribosome biogenesis exerts a regulatory function on normal erythroid development is still unknown. In the present study, a detailed characterization of ribosome biogenesis dynamics during human and murine erythropoiesis shows that ribosome biogenesis is abruptly interrupted by the drop of rDNA transcription and the collapse of ribosomal protein neo-synthesis. Its premature arrest by RNA polI inhibitor, CX-5461 targets the proliferation of immature erythroblasts. We also show that p53 is activated spontaneously or in response to CX-5461 concomitantly to ribosome biogenesis arrest, and drives a transcriptional program in which genes involved in cell cycle arrest, negative regulation of apoptosis and DNA damage response were upregulated. RNA polI transcriptional stress results in nucleolar disruption and activation of ATR-CHK1-p53 pathway. Our results imply that the timing of ribosome biogenesis extinction and p53 activation are crucial for erythroid development. In ribosomopathies in which ribosome availability is altered by unbalanced production of ribosomal proteins, the threshold of ribosome biogenesis down-regulation could be prematurely reached and together with pathological p53 activation prevents a normal expansion of erythroid progenitors.
2020-09-14 | GSE137951 | GEO
Project description:Ubiquitination controls most cellular processes, and its deregulation is associated to many pathologies. The Nse1 subunit in the Smc5/6 complex contains a RING domain with ubiquitin E3 ligase activity and important functions in genome integrity. However, Nse1-dependent ubiquitin targets remain largely unknown. Here, we use label-free quantitative proteomics to analyse the nuclear ubiquitinome of nse1 RING mutant cells. Our results show that Nse1 impacts on the ubiquitination of several proteins involved in DNA damage tolerance, ribosome biogenesis and metabolism that, importantly, extend beyond canonical functions of the Smc5/6 complex in chromosome segregation. In addition, our analysis uncovers an unexpected connection between Nse1 and Pol I ubiquitination. Specifically, Nse1 promotes the ubiquitination of K408 and K410 in Rpa190, the largest subunit of Pol I, to induce its degradation. We propose that this mechanism contributes to Smc5/6-dependent rDNA disjunction in response to transcriptional elongation defects.
2023-05-05 | PXD028669 | Pride