scholarly journals Human Papillomavirus and the DNA Damage Response: Exploiting Host Repair Pathways for Viral Replication

Viruses ◽  
2017 ◽  
Vol 9 (8) ◽  
pp. 232 ◽  
Author(s):  
Chelsey Spriggs ◽  
Laimonis Laimins
2015 ◽  
Vol 90 (5) ◽  
pp. 2639-2652 ◽  
Author(s):  
William H. Chappell ◽  
Dipendra Gautam ◽  
Suzan T. Ok ◽  
Bryan A. Johnson ◽  
Daniel C. Anacker ◽  
...  

ABSTRACTHigh-risk human papillomavirus 31 (HPV31)-positive cells exhibit constitutive activation of the ATM-dependent DNA damage response (DDR), which is necessary for productive viral replication. In response to DNA double-strand breaks (DSBs), ATM activation leads to DNA repair through homologous recombination (HR), which requires the principal recombinase protein Rad51, as well as BRCA1. Previous studies from our lab demonstrated that Rad51 and BRCA1 are expressed at high levels in HPV31-positive cells and localize to sites of viral replication. These results suggest that HPV may utilize ATM activity to increase HR activity as a means to facilitate viral replication. In this study, we demonstrate that high-risk HPV E7 expression alone is sufficient for the increase in Rad51 and BRCA1 protein levels. We have found that this increase occurs, at least in part, at the level of transcription. Studies analyzing protein stability indicate that HPV may also protect Rad51 and BRCA1 from turnover, contributing to the overall increase in cellular levels. We also demonstrate that Rad51 is bound to HPV31 genomes, with binding increasing per viral genome upon productive replication. We have found that depletion of Rad51 and BRCA1, as well as inhibition of Rad51's recombinase activity, abrogates productive viral replication upon differentiation. Overall, these results indicate that Rad51 and BRCA1 are required for the process of HPV31 genome amplification and suggest that productive replication occurs in a manner dependent upon recombination.IMPORTANCEProductive replication of HPV31 requires activation of an ATM-dependent DNA damage response, though how ATM activity contributes to replication is unclear. Rad51 and BRCA1 play essential roles in repair of double-strand breaks, as well as the restart of stalled replication forks through homologous recombination (HR). Given that ATM activity is required to initiate HR repair, coupled with the requirement of Rad51 and BRCA1 for productive viral replication, our findings suggest that HPV may utilize ATM activity to ensure localization of recombination factors to productively replicating viral genomes. The finding that E7 increases the levels of Rad51 and BRCA1 suggests that E7 contributes to productive replication by providing DNA repair factors required for viral DNA synthesis. Our studies not only imply a role for recombination in the regulation of productive HPV replication but provide further insight into how HPV manipulates the DDR to facilitate the productive phase of the viral life cycle.


2007 ◽  
Vol 1 (4) ◽  
pp. 275-286 ◽  
Author(s):  
Vera L. Tarakanova ◽  
Van Leung-Pineda ◽  
Seungmin Hwang ◽  
Chiao-Wen Yang ◽  
Katie Matatall ◽  
...  

2011 ◽  
Vol 85 (23) ◽  
pp. 12547-12556 ◽  
Author(s):  
N. Huang ◽  
W. Wu ◽  
K. Yang ◽  
A. L. Passarelli ◽  
G. F. Rohrmann ◽  
...  

Author(s):  
Kalyan Mahapatra ◽  
Samrat Banerjee ◽  
Sayanti De ◽  
Mehali Mitra ◽  
Pinaki Roy ◽  
...  

Besides the nuclear genome, plants possess two small extra chromosomal genomes in mitochondria and chloroplast, respectively, which contribute a small fraction of the organelles’ proteome. Both mitochondrial and chloroplast DNA have originated endosymbiotically and most of their prokaryotic genes were either lost or transferred to the nuclear genome through endosymbiotic gene transfer during the course of evolution. Due to their immobile nature, plant nuclear and organellar genomes face continuous threat from diverse exogenous agents as well as some reactive by-products or intermediates released from various endogenous metabolic pathways. These factors eventually affect the overall plant growth and development and finally productivity. The detailed mechanism of DNA damage response and repair following accumulation of various forms of DNA lesions, including single and double-strand breaks (SSBs and DSBs) have been well documented for the nuclear genome and now it has been extended to the organelles also. Recently, it has been shown that both mitochondria and chloroplast possess a counterpart of most of the nuclear DNA damage repair pathways and share remarkable similarities with different damage repair proteins present in the nucleus. Among various repair pathways, homologous recombination (HR) is crucial for the repair as well as the evolution of organellar genomes. Along with the repair pathways, various other factors, such as the MSH1 and WHIRLY family proteins, WHY1, WHY2, and WHY3 are also known to be involved in maintaining low mutation rates and structural integrity of mitochondrial and chloroplast genome. SOG1, the central regulator in DNA damage response in plants, has also been found to mediate endoreduplication and cell-cycle progression through chloroplast to nucleus retrograde signaling in response to chloroplast genome instability. Various proteins associated with the maintenance of genome stability are targeted to both nuclear and organellar compartments, establishing communication between organelles as well as organelles and nucleus. Therefore, understanding the mechanism of DNA damage repair and inter compartmental crosstalk mechanism in various sub-cellular organelles following induction of DNA damage and identification of key components of such signaling cascades may eventually be translated into strategies for crop improvement under abiotic and genotoxic stress conditions. This review mainly highlights the current understanding as well as the importance of different aspects of organelle genome maintenance mechanisms in higher plants.


2021 ◽  
Author(s):  
Thomas Walker ◽  
Zahra Faraahi ◽  
marcus price ◽  
Amy Hawarden ◽  
Catlin Waddell ◽  
...  

Defective DNA damage response (DDR) pathways allow cancer cells to accrue genomic aberrations and evade normal cellular growth checkpoints. Defective DDR also determines response to chemotherapy. However, the interaction and overlap between the two double strand repair pathways and the three single strand repair pathways is complex, and has remained poorly understood. Here we show that, in ovarian cancer, a disease hallmarked by chromosomal instability, explant cultures show a range of DDR abrogation patterns. Defective homologous recombination (HR) and non-homologous end joining (NHEJ) are near mutually exclusive with HR deficient (HRD) cells showing increased abrogation of the single strand repair pathways compared to NHEJ defective cells. When combined with global markers of DNA damage, including mitochondrial membrane functionality and reactive oxygen species burden, the pattern of DDR abrogation allows the construction of DDR signatures which are predictive of both ex vivo cytotoxicity, and more importantly, patient outcome.


2015 ◽  
Vol 89 (9) ◽  
pp. 5032-5039 ◽  
Author(s):  
Brandy Verhalen ◽  
Joshua L. Justice ◽  
Michael J. Imperiale ◽  
Mengxi Jiang

ABSTRACTBK polyomavirus (BKPyV) reactivation is associated with severe human disease in kidney and bone marrow transplant patients. The interplay between viral and host factors that regulates the productive infection process remains poorly understood. We have previously reported that the cellular DNA damage response (DDR) is activated upon lytic BKPyV infection and that its activation is required for optimal viral replication in primary kidney epithelial cells. In this report, we set out to determine what viral components are responsible for activating the two major phosphatidylinositol 3-kinase-like kinases (PI3KKs) involved in the DDR: ataxia telangiectasia mutated (ATM) kinase and ATM and Rad3-related (ATR) kinase. Using a combination of UV treatment, lentivirus transduction, and mutant virus infection experiments, our results demonstrate that neither the input virus nor the expression of large T antigen (TAg) alone is sufficient to trigger the activation of ATM or ATR in our primary culture model. Instead, our data suggest that the activation of both the ATM- and ATR-mediated DDR pathways is linked to viral DNA replication. Intriguingly, a TAg mutant virus that is unable to activate the DDR causes substantial host DNA damage. Our study provides insight into how DDRs are activated by polyomaviruses in primary cells with intact cell cycle checkpoints and how the activation might be linked to the maintenance of host genome stability.IMPORTANCEPolyomaviruses are opportunistic pathogens that are associated with several human diseases under immunosuppressed conditions. BK polyomavirus (BKPyV) affects mostly kidney and bone marrow transplant patients. The detailed replication mechanism of these viruses remains to be determined. We have previously reported that BKPyV activates the host DNA damage response (DDR), a response normally used by the host cell to combat genotoxic stress, to aid its own replication. In this study, we identified that the trigger for DDR activation is viral replication. Furthermore, we show that the virus is able to cause host DNA damage in the absence of viral replication and DDR activation. These results suggest an intricate relationship between viral replication, DDR activation, and host genome instability.


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