scholarly journals RNR-R2 Upregulation by a Short Non-Coding Viral Transcript

Biomolecules ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1822
Author(s):  
Karin Broennimann ◽  
Inna Ricardo-Lax ◽  
Julia Adler ◽  
Eleftherios Michailidis ◽  
Ype P. de Jong ◽  
...  
Keyword(s):  
Dna Damage Response ◽  
Regulatory Element ◽  
Human Hepatocytes ◽  
Viral Transcript ◽  
Dna Viruses ◽  
Reading Frame ◽  
Intracellular Dntp ◽  
B Virus ◽  
Damage Response ◽  
Dividing Cells

DNA viruses require dNTPs for replication and have developed different strategies to increase intracellular dNTP pools. Hepatitis B virus (HBV) infects non-dividing cells in which dNTPs are scarce and the question is how viral replication takes place. Previously we reported that the virus induces the DNA damage response (DDR) pathway culminating in RNR-R2 expression and the generation of an active RNR holoenzyme, the key regulator of dNTP levels, leading to an increase in dNTPs. How the virus induces DDR and RNR-R2 upregulation is not completely known. The viral HBx open reading frame (ORF) was believed to trigger this pathway. Unexpectedly, however, we report here that the production of HBx protein is dispensable. We found that a small conserved region of 125 bases within the HBx ORF is sufficient to upregulate RNR-R2 expression in growth-arrested HepG2 cells and primary human hepatocytes. The observed HBV mRNA embedded regulatory element is named ERE. ERE in isolation is sufficient to activate the ATR-Chk1-E2F1-RNR-R2 DDR pathway. These findings demonstrate a non-coding function of HBV transcripts to support its propagation in non-cycling cells.

scholarly journals A short HBV RNA region induces RNR-R2 expression in non-cycling cells and in primary human hepatocytes

2018 ◽  
Author(s):  
Inna Ricardo-Lax ◽  
Karin Broennimann ◽  
Julia Adler ◽  
Eleftherios Michailidis ◽  
Ype P de Jong ◽  
...  
Keyword(s):  
Dna Damage ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Dna Damage Response ◽  
Human Hepatocytes ◽  
Host Cells ◽  
Primary Human Hepatocytes ◽  
B Virus ◽  
Damage Response ◽  
Cellular Dna

AbstractHepatitis B virus infects non-dividing cells in which dNTPs are scarce. HBV replication requires dNTPs. To cope with this constraint the virus induces the DNA damage response (DDR) pathway culminating in RNR-R2 expression and the generation of an active RNR holoenzyme, the key regulator of dNTP levels. Previously we reported that the HBx open reading frame (ORF) triggers this pathway. Unexpectedly however, we report here that the production of HBx protein is not essential. We found that a small region of 125 bases within the HBx transcript is sufficient to induce RNR-R2 expression in growth arrested HepG2 cells and in primary human hepatocytes (PHH). The observed HBx embedded regulatory element is named ERE. We demonstrate that ERE is functional as a positive strand RNA polymerase-II transcript. Remarkably, ERE is sufficient to induce the Chk1-E2F1-RNR-R2 DDR pathway, previously reported to be activated by HBV. Furthermore, we found that ERE activates ATR but not ATM in eliciting this DDR pathway in upregulating RNR-R2. These findings demonstrate the multitasking role of HBV transcripts in mediating virus-host cell interaction, a mechanism that explains how such a small genome effectively serves such a pervasive virus.Author summaryThe hepatitis B virus (HBV) infects the human liver and over 250 million people worldwide are chronically infected with HBV and at risk for cirrhosis and liver cancer. HBV has a very small DNA genome with only four genes, much fewer than other viruses. For propagation the virus consumes dNTPs, the building blocks of DNA, in much higher amounts than the infected cells provide. To cope with this constraint, the virus manipulates the cells to increase the production of dNTPs. We found that the virus activates the cellular response to DNA damage upon which the cells increase the production of dNTPs, but instead of repairing cellular DNA, the virus uses them for production of its own DNA. Usually viruses manipulate host cells with one or more of their unique proteins, however the small HBV genome cannot afford having such a unique gene and protein. Instead, we found that here the virus relies on RNA to manipulate the host cells. Our findings highlight the unprecedented principle of a multitasking viral RNA that is not only designed to be translated into proteins but also harbors an independent role in activating the cellular DNA damage response.

scholarly journals High Fidelity Deep Sequencing Reveals No Effect of ATM, ATR, and DNA-PK Cellular DNA Damage Response Pathways on Adenovirus Mutation Rate

Viruses ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 938 ◽  
Author(s):  
Risso-Ballester ◽  
Sanjuán
Keyword(s):  
Dna Damage ◽  
Protein Kinase ◽  
Dna Damage Response ◽  
Deep Sequencing ◽  
Molecular Mechanisms ◽  
Spontaneous Mutation ◽  
High Fidelity ◽  
Dna Viruses ◽  
Damage Response ◽  
Cellular Dna

Most DNA viruses exhibit relatively low rates of spontaneous mutation. However, the molecular mechanisms underlying DNA virus genetic stability remain unclear. In principle, mutation rates should not depend solely on polymerase fidelity, but also on factors such as DNA damage and repair efficiency. Most eukaryotic DNA viruses interact with the cellular DNA damage response (DDR), but the role of DDR pathways in preventing mutations in the virus has not been tested empirically. To address this goal, we serially transferred human adenovirus type 5 in cells in which the telangiectasia-mutated PI3K-related protein kinase (ATM), the ATM/Rad3-related (ATR) kinase, and the DNA-dependent protein kinase (DNA-PK) were chemically inactivated, as well as in control cells displaying normal DDR pathway functioning. High-fidelity deep sequencing of these viral populations revealed mutation frequencies in the order of one-millionth, with no detectable effect of the inactivation of DDR mediators ATM, ATR, and DNA-PK on adenovirus sequence variability. This suggests that these DDR pathways do not play a major role in determining adenovirus genetic diversity.

scholarly journals Virus DNA Replication and the Host DNA Damage Response

2018 ◽  
Vol 5 (1) ◽  
pp. 141-164 ◽  
Author(s):  
Matthew D. Weitzman ◽  
Amélie Fradet-Turcotte
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Life Cycles ◽  
Dynamic Interactions ◽  
Dna Damage And Repair ◽  
Dna Viruses ◽  
Cellular Processes ◽  
Damage Response ◽  
Cellular Replication ◽  
Cellular Dna

Viral DNA genomes have limited coding capacity and therefore harness cellular factors to facilitate replication of their genomes and generate progeny virions. Studies of viruses and how they interact with cellular processes have historically provided seminal insights into basic biology and disease mechanisms. The replicative life cycles of many DNA viruses have been shown to engage components of the host DNA damage and repair machinery. Viruses have evolved numerous strategies to navigate the cellular DNA damage response. By hijacking and manipulating cellular replication and repair processes, DNA viruses can selectively harness or abrogate distinct components of the cellular machinery to complete their life cycles. Here, we highlight consequences for viral replication and host genome integrity during the dynamic interactions between virus and host.

scholarly journals Hepatitis B Virus and DNA Damage Response: Interactions and Consequences for the Infection

Viruses ◽  
2017 ◽  
Vol 9 (10) ◽  
pp. 304 ◽  
Author(s):  
Andoni Gómez-Moreno ◽  
Urtzi Garaigorta
Keyword(s):  
Dna Damage ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Dna Damage Response ◽  
B Virus ◽  
Damage Response

scholarly journals Werner Protein Protects Nonproliferating Cells from Oxidative DNA Damage

2005 ◽  
Vol 25 (23) ◽  
pp. 10492-10506 ◽  
Author(s):  
Anna M. Szekely ◽  
Franziska Bleichert ◽  
Astrid Nümann ◽  
Stephen Van Komen ◽  
Elisabeth Manasanch ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Oxidative Dna Damage ◽  
Werner Syndrome ◽  
Human Fibroblasts ◽  
Telomere Maintenance ◽  
Telomere Binding Protein ◽  
Damage Response ◽  
Dividing Cells

ABSTRACT Werner syndrome, caused by mutations of the WRN gene, mimics many changes of normal aging. Although roles for WRN protein in DNA replication, recombination, and telomere maintenance have been suggested, the pathology of rapidly dividing cells is not a feature of Werner syndrome. To identify cellular events that are specifically vulnerable to WRN deficiency, we used RNA interference (RNAi) to knockdown WRN or BLM (the RecQ helicase mutated in Bloom syndrome) expression in primary human fibroblasts. Withdrawal of WRN or BLM produced accelerated cellular senescence phenotype and DNA damage response in normal fibroblasts, as evidenced by induction of γH2AX and 53BP1 nuclear foci. After WRN depletion, the induction of these foci was seen most prominently in nondividing cells. Growth in physiological (3%) oxygen or in the presence of an antioxidant prevented the development of the DNA damage foci in WRN-depleted cells, whereas acute oxidative stress led to inefficient repair of the lesions. Furthermore, WRN RNAi-induced DNA damage was suppressed by overexpression of the telomere-binding protein TRF2. These conditions, however, did not prevent the DNA damage response in BLM-ablated cells, suggesting a distinct role for WRN in DNA homeostasis in vivo. Thus, manifestations of Werner syndrome may reflect an impaired ability of slowly dividing cells to limit oxidative DNA damage.

Hepatitis B virus induces RNR-R2 expression via DNA damage response activation

2015 ◽  
Vol 63 (4) ◽  
pp. 789-796 ◽  
Author(s):  
Inna Ricardo-Lax ◽  
Vyas Ramanan ◽  
Eleftherios Michailidis ◽  
Tal Shamia ◽  
Nina Reuven ◽  
...  
Keyword(s):  
Dna Damage ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Dna Damage Response ◽  
B Virus ◽  
Damage Response ◽  
Response Activation

scholarly journals ATR regulates neuronal activity by modulating presynaptic firing

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Murat Kirtay ◽  
Josefine Sell ◽  
Christian Marx ◽  
Holger Haselmann ◽  
Mihai Ceanga ◽  
...  
Keyword(s):  
Dna Damage ◽  
Neuronal Activity ◽  
Dna Damage Response ◽  
Ataxia Telangiectasia ◽  
Physiological Function ◽  
Epileptiform Activity ◽  
Damage Response ◽  
Dividing Cells ◽  
Presynaptic Vesicle ◽  
Essential Function

AbstractAtaxia Telangiectasia and Rad3-related (ATR) protein, as a key DNA damage response (DDR) regulator, plays an essential function in response to replication stress and controls cell viability. Hypomorphic mutations of ATR cause the human ATR-Seckel syndrome, characterized by microcephaly and intellectual disability, which however suggests a yet unknown role for ATR in non-dividing cells. Here we show that ATR deletion in postmitotic neurons does not compromise brain development and formation; rather it enhances intrinsic neuronal activity resulting in aberrant firing and an increased epileptiform activity, which increases the susceptibility of ataxia and epilepsy in mice. ATR deleted neurons exhibit hyper-excitability, associated with changes in action potential conformation and presynaptic vesicle accumulation, independent of DDR signaling. Mechanistically, ATR interacts with synaptotagmin 2 (SYT2) and, without ATR, SYT2 is highly upregulated and aberrantly translocated to excitatory neurons in the hippocampus, thereby conferring a hyper-excitability. This study identifies a physiological function of ATR, beyond its DDR role, in regulating neuronal activity.

scholarly journals Saccharomyces cerevisiae Dap1p, a Novel DNA Damage Response Protein Related to the Mammalian Membrane-Associated Progesterone Receptor

2003 ◽  
Vol 2 (2) ◽  
pp. 306-317 ◽  
Author(s):  
Randal A. Hand ◽  
Nan Jia ◽  
Martin Bard ◽  
Rolf J. Craven
Keyword(s):  
Dna Damage Response ◽  
Cell Cycle Progression ◽  
Progesterone Receptors ◽  
Sterol Synthesis ◽  
Methyl Methanesulfonate ◽  
Cycle Progression ◽  
Reading Frame ◽  
Cellular Survival ◽  
Damage Response ◽  
Broad Array

ABSTRACT The response to damage is crucial for cellular survival, and eukaryotic cells require a broad array of proteins for an intact damage response. We have found that the YPL170W (DAP1 [for damage response protein related to membrane-associated progesterone receptors]) gene is required for growth in the presence of the methylating agent methyl methanesulfonate (MMS). The DAP1 open reading frame shares homology with a broadly conserved family of membrane-associated progesterone receptors (MAPRs). Deletion of DAP1 leads to sensitivity to MMS, elongated telomeres, loss of mitochondrial function, and partial arrest in sterol synthesis. Sensitivity of dap1 strains to MMS is not due to loss of damage checkpoints. Instead, dap1 cells are arrested as unbudded cells after MMS treatment, suggesting that Dap1p is required for cell cycle progression following damage. Dap1p also directs resistance to itraconazole and fluconazole, inhibitors of sterol synthesis. We have found that dap1 cells have slightly decreased levels of ergosterol but increased levels of the ergosterol intermediates squalene and lanosterol, indicating that dap1 cells have a partial defect in sterol synthesis. This is the first evidence linking a MAPR family member to sterol regulation or the response to damage, and these functions are probably conserved in a variety of eukaryotes.

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