Chromatin damage generated by DNA intercalators leads to degradation of RNA Polymerase II

Nucleic Acids Research, Journal Year: 2024, Volume and Issue: 52(8), P. 4151 - 4166

Published: Feb. 10, 2024

Abstract In cancer therapy, DNA intercalators are mainly known for their capacity to kill cells by inducing damage. Recently, several have attracted much interest given ability inhibit RNA Polymerase I transcription (BMH-21), evict histones (Aclarubicin) or induce chromatin trapping of FACT (Curaxin CBL0137). Interestingly, these lack the damage while still retaining cytotoxic effects and stabilize p53. Herein, we report that impact biology interfering with stability polymerases I, II III. These three compounds degradation polymerase they simultaneously enable Topoisomerases TOP2A TOP2B on chromatin. addition, BMH-21 also acts as a catalytic inhibitor Topoisomerase II, resembling Aclarubicin. Moreover, induces histone chaperone propels accumulation Z-DNA eviction, similarly Aclarubicin CBL0137. cumulative general machinery topological defects impacting nuclear Therefore, capabilities may be result compounding deleterious homeostasis.

Language: Английский

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Keep calm and reboot – how cells restart transcription after DNA damage and DNA repair

FEBS Letters, Journal Year: 2024, Volume and Issue: unknown

Published: July 11, 2024

The effects of genotoxic agents on DNA and the processes involved in their removal have been thoroughly studied; however, very little is known about mechanisms governing reinstatement cellular activities after repair, despite restoration damage‐induced block transcription being essential for cell survival. In addition to impeding transcription, lesions potential disrupt precise positioning chromatin domains within nucleus alter meticulously organized architecture nucleolus. Alongside necessity resuming mediated by RNA polymerase 1 2 it crucial restore structure nucleolus facilitate optimal ribosome biogenesis ensure efficient error‐free translation. Here, we examine current understanding how transcriptional activity from reinstated following repair completion explore reassembling safeguard correct progression functions. Given lack information this vital function, Review seeks inspire researchers deeper into specific subject offers suggestions investigate complex nearly unexplored process further.

Language: Английский

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The Nucleolus: A Central Hub for Ribosome Biogenesis and Cellular Regulatory Signals

International Journal of Molecular Sciences, Journal Year: 2025, Volume and Issue: 26(9), P. 4174 - 4174

Published: April 28, 2025

The nucleolus is the most prominent nuclear domain in eukaryotic cells, primarily responsible for ribosome biogenesis. It synthesizes and processes precursor ribosomal RNA (pre-rRNA) into mature rRNAs, assembling 40S 60S subunits, which later form 80S ribosome-the essential molecular machine protein synthesis. Beyond production, lacks a delimiting membrane, allowing it to rapidly regulate cellular homeostasis by sequestering key stress response factors. This adaptability enables dynamic changes size, number, composition signaling. Recent research highlights as critical regulator of chemoresistance. Given its central role cell survival adaptation, has become an attractive therapeutic target, particularly cancer treatment. A deeper understanding nucleolar metabolism could pave way novel strategies against various human diseases.

Language: Английский

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Telomere biology and ribosome biogenesis: structural and functional interconnections

Biochemistry and Cell Biology, Journal Year: 2023, Volume and Issue: 101(5), P. 394 - 409

Published: March 29, 2023

Telomeres are nucleoprotein structures that play a pivotal role in the protection and maintenance of eukaryotic chromosomes. enzyme telomerase, which replenishes telomeric DNA lost during replication, important factors necessary to ensure continued cell proliferation. Cell proliferation is also dependent on proper efficient protein synthesis, carried out by ribosomes. Mutations genes involved either ribosome biogenesis or telomere biology result cellular abnormalities can cause human genetic diseases, defined as ribosomopathies telomeropathies, respectively. Interestingly, recent discoveries indicate many assembly rRNA maturation have additional noncanonical functions biology. Similarly, several key proteins enzymes biology, including unexpected roles transcription maturation. These observations point an intriguing cross-talk mechanism potentially explaining multiple pleiotropic symptoms mutations causal identified various telomeropathy ribosomopathy diseases. In this review, we provide brief summary rDNA loci structures, highlight universal features telomerase biogenesis, evaluate interconnections between assembly, conclude with assessment overlapping diseases telomeropathies ribosomopathies.

Language: Английский

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Synthesis of the ribosomal RNA precursor in human cells: mechanisms, factors and regulation

Biological Chemistry, Journal Year: 2023, Volume and Issue: 404(11-12), P. 1003 - 1023

Published: July 16, 2023

The ribosomal RNA precursor (pre-rRNA) comprises three of the four RNAs and is synthesized by polymerase (Pol) I. Here, we describe mechanisms Pol I transcription in human cells with a focus on recent insights gained from structure-function analyses. comparison I-specific structural functional features those other Pols excessively studied yeast system distinguishes organism-specific general traits. We explain organization genomic rDNA loci cells, cycle regarding changes enzyme roles subunits, depict factors their function mechanistic level. disentangle information direct investigation what had apparently been deduced studies enzymes. Finally, provide about how mutations may contribute to developmental diseases, why target for new cancer treatment strategies, since increased rRNA synthesis was correlated rapidly expanding cell populations.

Language: Английский

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Transcription factor UBF depletion in mouse cells results in downregulation of both downstream and upstream elements of the rRNA transcription network

Journal of Biological Chemistry, Journal Year: 2023, Volume and Issue: 299(10), P. 105203 - 105203

Published: Sept. 1, 2023

Transcription/processing of the ribosomal RNA (rRNA) precursor, as part ribosome biosynthesis, is intensively studied and characterized in eukaryotic cells. Here, we constructed shRNA-based mouse cell lines partially silenced for Upstream Binding Factor UBF, master regulator rRNA transcription organizer open rDNA chromatin. Full Ubf silencing vivo not viable, these new tools allow further characterization its coordination with cellular signaling. shUBF cells display cycle G1 delay reduced 47S precursor 28S at baseline serum-challenged conditions. Growth-related mTOR signaling downregulated fractions active phospho-S6 Kinase pEIF4E translation initiation factor reduced, similar to phosphorylated retinoblastoma, pRB, positive UBF availability/rRNA transcription. Additionally, find transcription-competent pUBF (Ser484) severely restricted interacting RRN3 responsive extracellular cues. Furthermore, fractional occupancy on unit decreased shUBF, expression major factors involved different aspects by depletion. Finally, observe Pol1 over promoter sequences identified unexpected regulation expression, relative serum availability under silencing, suggesting that may be modulation binding/elongation rate. Overall, this work reveals depletion has a critical downstream upstream impact whole network orchestrating mammalian

Language: Английский

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The cytidine deaminase APOBEC3A regulates nucleolar function to promote cell growth and ribosome biogenesis

PLoS Biology, Journal Year: 2024, Volume and Issue: 22(7), P. e3002718 - e3002718

Published: July 8, 2024

Cancer initiates as a consequence of genomic mutations and its subsequent progression relies in part on increased production ribosomes to maintain high levels protein synthesis for unchecked cell growth. Recently, cytidine deaminases have been uncovered sources mutagenesis cancer. In an attempt form connection between these 2 cancer driving processes, we interrogated the deaminase family proteins potential roles human ribosome biogenesis. We identified validated APOBEC3A APOBEC4 novel biogenesis factors through our laboratory’s established screening platform discovery regulators nucleolar function MCF10A cells. Through siRNA depletion experiments, highlight APOBEC3A’s requirement making specific role within processing maturation steps that large subunit 5.8S 28S ribosomal (r)RNAs. demonstrate subset resides nucleolus associates with critical factors. Mechanistic insight was revealed by transient overexpression both wild-type catalytically dead mutated APOBEC3A, which increase growth synthesis. innovative nuclear RNA sequencing methodology, identify only modest predicted C-to-U target sites pre-rRNA pre-mRNAs. Our work reveals direct likely independent editing function. More broadly, found additional pathology biogenesis, expanding relevance therapeutics.

Language: Английский

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Expression of RNA polymerase I catalytic core is influenced by RPA12

PLoS ONE, Journal Year: 2023, Volume and Issue: 18(5), P. e0285660 - e0285660

Published: May 11, 2023

RNA Polymerase I (Pol I) has recently been recognized as a cancer therapeutic target. The activity of this enzyme is essential for ribosome biogenesis and universally activated in cancers. enzymatic multi-subunit complex resides its catalytic core composed RPA194, RPA135, RPA12, subunit with functions cleavage, transcription initiation elongation. Here we explore whether RPA12 influences the regulation RPA194 human cells. We use specific small-molecule Pol inhibitor BMH-21 that inhibits initiation, elongation ultimately activates degradation RPA194. show silencing causes alterations expression localization subunits RPA135. Furthermore, find despite these not only does between RPA135 remain intact upon knockdown, but engagement chromatin unaffected. BMH-21-mediated was independent suggesting affects basal expression, drug-inducible turnover These studies add to knowledge defining regulatory factors subunit.

Language: Английский

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Ribosomal RNA transcription governs splicing through ribosomal protein RPL22

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Aug. 16, 2024

Abstract Ribosome biosynthesis is a cancer vulnerability executed by targeting RNA polymerase I (Pol I) transcription. We developed advanced, specific Pol inhibitors to identify drivers of this sensitivity. By integrating multi-omics features and drug sensitivity data from large cell panel, we discovered that RPL22 frameshift mutation conferred inhibitor in microsatellite instable cancers. Mechanistically, directly interacts with 28S rRNA mRNA splice junctions, functioning as splicing regulator. deficiency, intensified sequestration, promoted the its paralog RPL22L1 p53 negative regulator MDM4. Chemical genetic inhibition synthesis broadly remodeled controlling hundreds targets. Strikingly, RPL22-dependent alternative was reversed revealing ribotoxic stress-initiated tumor suppressive pathway. mechanism robustly connects activity reveals their coordination ribosomal protein RPL22.

Language: Английский

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Decoding the Molecular Script of 2’-O-Ribomethylation: Implications Across CNS Disorders

Heliyon, Journal Year: 2024, Volume and Issue: 10(21), P. e39036 - e39036

Published: Oct. 5, 2024

Emerging evidence underscores the critical role of impaired mRNA translation in various neurobiological conditions. Ribosomal RNA (rRNA), essential for protein synthesis, undergoes crucial post-transcriptional modifications such as 2'-O-ribose methylation, pseudouridylation, and base modifications. These modifications, particularly methylation is vital stabilizing rRNA structures optimizing efficiency by regulating integrity its interactions with proteins. Concentrated key regions like decoding sites peptidyl transferase center, dysregulation these can disrupt ribosomal function, contributing to pathogenesis diverse neurological conditions, including mental health disorders, developmental abnormalities, neurodegenerative diseases. Mechanistically, involves between small nucleolar RNAs (snoRNAs), snoRNPs, fibrillarin, forming a complex regulatory network maintaining function. Recent research highlights association defective ribosome biogenesis spectrum CNS emphasizing importance understanding mechanisms disease pathology. This review focuses on pivotal shaping function potential implications unraveling pathophysiology disorders. Insights gained from studying could pave way new therapeutic strategies targeting dysfunction associated neuropathological advancing precision medicine interventions.

Language: Английский

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