scholarly journals Human Parvovirus B19 Utilizes Cellular DNA Replication Machinery for Viral DNA Replication

2017 ◽  
Vol 92 (5) ◽  
Author(s):  
Wei Zou ◽  
Zekun Wang ◽  
Min Xiong ◽  
Aaron Yun Chen ◽  
Peng Xu ◽  
...  

ABSTRACTHuman parvovirus B19 (B19V) infection of human erythroid progenitor cells (EPCs) induces a DNA damage response and cell cycle arrest at late S phase, which facilitates viral DNA replication. However, it is not clear exactly which cellular factors are employed by this single-stranded DNA virus. Here, we used microarrays to systematically analyze the dynamic transcriptome of EPCs infected with B19V. We found that DNA metabolism, DNA replication, DNA repair, DNA damage response, cell cycle, and cell cycle arrest pathways were significantly regulated after B19V infection. Confocal microscopy analyses revealed that most cellular DNA replication proteins were recruited to the centers of viral DNA replication, but not the DNA repair DNA polymerases. Our results suggest that DNA replication polymerase δ and polymerase α are responsible for B19V DNA replication by knocking down its expression in EPCs. We further showed that although RPA32 is essential for B19V DNA replication and the phosphorylated forms of RPA32 colocalized with the replicating viral genomes, RPA32 phosphorylation was not necessary for B19V DNA replication. Thus, this report provides evidence that B19V uses the cellular DNA replication machinery for viral DNA replication.IMPORTANCEHuman parvovirus B19 (B19V) infection can cause transient aplastic crisis, persistent viremia, and pure red cell aplasia. In fetuses, B19V infection can result in nonimmune hydrops fetalis and fetal death. These clinical manifestations of B19V infection are a direct outcome of the death of human erythroid progenitors that host B19V replication. B19V infection induces a DNA damage response that is important for cell cycle arrest at late S phase. Here, we analyzed dynamic changes in cellular gene expression and found that DNA metabolic processes are tightly regulated during B19V infection. Although genes involved in cellular DNA replication were downregulated overall, the cellular DNA replication machinery was tightly associated with the replicating single-stranded DNA viral genome and played a critical role in viral DNA replication. In contrast, the DNA damage response-induced phosphorylated forms of RPA32 were dispensable for viral DNA replication.

2013 ◽  
Vol 87 (23) ◽  
pp. 12766-12775 ◽  
Author(s):  
Yong Luo ◽  
Steve Kleiboeker ◽  
Xuefeng Deng ◽  
Jianming Qiu

Human parvovirus B19 (B19V) infection has a unique tropism to human erythroid progenitor cells (EPCs) in human bone marrow and the fetal liver. It has been reported that both B19V infection and expression of the large nonstructural protein NS1 arrested EPCs at a cell cycle status with a 4 N DNA content, which was previously claimed to be “G2/M arrest.” However, a B19V mutant infectious DNA (M20mTAD2) replicated well in B19V-semipermissive UT7/Epo-S1 cells but did not induce G2/M arrest (S. Lou, Y. Luo, F. Cheng, Q. Huang, W. Shen, S. Kleiboeker, J. F. Tisdale, Z. Liu, and J. Qiu, J. Virol.86:10748–10758, 2012). To further characterize cell cycle arrest during B19V infection of EPCs, we analyzed the cell cycle change using 5-bromo-2′-deoxyuridine (BrdU) pulse-labeling and DAPI (4′,6-diamidino-2-phenylindole) staining, which precisely establishes the cell cycle pattern based on both cellular DNA replication and nuclear DNA content. We found that although both B19V NS1 transduction and infection immediately arrested cells at a status of 4 N DNA content, B19V-infected 4 N cells still incorporated BrdU, indicating active DNA synthesis. Notably, the BrdU incorporation was caused neither by viral DNA replication nor by cellular DNA repair that could be initiated by B19V infection-induced cellular DNA damage. Moreover, several S phase regulators were abundantly expressed and colocalized within the B19V replication centers. More importantly, replication of the B19V wild-type infectious DNA, as well as the M20mTAD2mutant, arrested cells at S phase. Taken together, our results confirmed that B19V infection triggers late S phase arrest, which presumably provides cellular S phase factors for viral DNA replication.


2009 ◽  
Vol 83 (9) ◽  
pp. 4565-4573 ◽  
Author(s):  
Kasey A. Karen ◽  
Peter J. Hoey ◽  
C. S. H. Young ◽  
Patrick Hearing

ABSTRACT Adenovirus infection induces a cellular DNA damage response that can inhibit viral DNA replication and ligate viral genomes into concatemers. It is not clear if the input virus is sufficient to trigger this response or if viral DNA replication is required. Adenovirus has evolved two mechanisms that target the Mre11-Rad50-Nbs1 (MRN) complex to inhibit the DNA damage response. These include E4-ORF3-dependent relocalization of MRN proteins and E4-ORF6/E1B-55K-dependent degradation of MRN components. The literature suggests that degradation of the MRN complex due to E4-ORF6/E1B-55K does not occur until after viral DNA replication has begun. We show that, by the time viral DNA accumulates, the MRN complex is inactivated by either of the E4-induced mechanisms and that, with E4-ORF6/E1B-55K, this inactivation is due to MRN degradation. Our data are consistent with the conclusion that input viral DNA is sufficient to induce the DNA damage response. Further, we demonstrate that when the DNA damage response is active in E4 mutant virus infections, the covalently attached terminal protein is not cleaved from viral DNAs, and the viral origins of replication are not detectably degraded at a time corresponding to the onset of viral replication. The sequences of concatemeric junctions of viral DNAs were determined, which supports the conclusion that nonhomologous end joining mediates viral DNA ligation. Large deletions were found at these junctions, demonstrating nucleolytic procession of the viral DNA; however, the lack of terminal protein cleavage and terminus degradation at earlier times shows that viral genome deletion and concatenation are late effects.


2010 ◽  
Vol 30 (7) ◽  
pp. 1607-1619 ◽  
Author(s):  
Cyril Ramathal ◽  
Indrani C. Bagchi ◽  
Milan K. Bagchi

ABSTRACT Female mice lacking the transcription factor C/EBPβ are infertile and display markedly reduced estrogen (E)-induced proliferation of the uterine epithelial lining during the reproductive cycle. The present study showed that E-stimulated luminal epithelial cells of a C/EBPβ-null uterus are able to proceed through the G1 phase of the cell cycle before getting arrested in the S phase. This cell cycle arrest was accompanied by markedly reduced levels of expression of E2F3, an E2F family member, and a lack of nuclear localization of cyclin E, a critical regulator of cdk2. An increased nuclear accumulation of p27, an inhibitor of the cyclin E-cdk2 complex, was also observed for the mutant epithelium. Gene expression profiling of C/EBPβ-null uterine epithelial cells revealed that the blockade of E-induced DNA replication triggers the activation of several well-known components of the DNA damage response pathway, such as ATM, ATR, histone H2AX, checkpoint kinase 1, and tumor suppressor p53. The activation of p53 by ATM/ATR kinase led to increased levels of expression of p21, an inhibitor of G1-S-phase progression, which helps maintain cell cycle arrest. Additionally, p53-dependent mechanisms contributed to an increased apoptosis of replication-defective cells in the C/EBPβ-null epithelium. C/EBPβ, therefore, is an essential mediator of E-induced growth and survival of uterine epithelial cells of cycling mice.


2021 ◽  
Author(s):  
Liting Shao ◽  
Kang Ning ◽  
Jianke Wang ◽  
Fang Cheng ◽  
Shengqi Wang ◽  
...  

Human bocavirus 1 (HBoV1), an autonomous human parvovirus, causes acute respiratory tract infections in young children. HBoV1 infects well-differentiated (polarized) human airway epithelium cultured at an air-liquid interface (HAE-ALI). HBoV1 expresses a large nonstructural protein, NS1, that is essential for viral DNA replication. HBoV1 infection of polarized human airway epithelial cells induces a DNA damage response (DDR) that is critical to viral DNA replication involving DNA repair with error-free Y-family DNA polymerases. HBoV1 NS1 or the isoform NS1-70 per se induces a DDR. In this study, using the second-generation proximity-dependent biotin identification (BioID2) approach, we identified that Ku70 is associated with the NS1-BioID2 pulldown complex through a direct interaction with NS1. Bio-layer Interferometry (BLI) assay determined a high binding affinity of the NS1 with Ku70, which has an equilibrium dissociation constant (K D ) value of 0.16 μM and processes the strongest interaction at the C-terminal domain. The association of Ku70 with NS1 was also revealed during HBoV1 infection of HAE-ALI. Knockdown of Ku70 and overexpression of the C-terminal domain of Ku70 significantly decreased HBoV1 replication in HAE-ALI. Thus, our study provides for the first time a direct interaction of a parvovirus large nonstructural protein NS1 with Ku70. IMPORTANCE Parvovirus infection induces a DNA damage response (DDR) that plays a pivotal role in viral DNA replication. The DDR includes activation of ATM (Ataxia telangiectasia mutated), ATR (ATM- and RAD3-related), and DNA-PKcs (DNA-dependent protein kinase catalytic subunit). The large nonstructural protein (NS1) often plays a role in the induction of DDR; however, how the DDR is induced during parvovirus infection or simply by the NS1 is not well studied. Activation of DNA-PKcs has been shown as one of the key DDR pathways in DNA replication of HBoV1. We identified that HBoV1 NS1 directly interacts with Ku70, but not Ku80, of the Ku70/Ku80 heterodimer at a high affinity. This interaction is also important for HBoV1 replication in HAE-ALI. We propose that the interaction of the NS1 with Ku70 recruits the Ku70/Ku80 complex to the viral DNA replication center, which activates DNA-PKcs and facilitates viral DNA replication.


2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Toshinori Ozaki ◽  
Akira Nakagawara ◽  
Hiroki Nagase

A proper DNA damage response (DDR), which monitors and maintains the genomic integrity, has been considered to be a critical barrier against genetic alterations to prevent tumor initiation and progression. The representative tumor suppressor p53 plays an important role in the regulation of DNA damage response. When cells receive DNA damage, p53 is quickly activated and induces cell cycle arrest and/or apoptotic cell death through transactivating its target genes implicated in the promotion of cell cycle arrest and/or apoptotic cell death such asp21WAF1,BAX, andPUMA. Accumulating evidence strongly suggests that DNA damage-mediated activation as well as induction of p53 is regulated by posttranslational modifications and also by protein-protein interaction. Loss of p53 activity confers growth advantage and ensures survival in cancer cells by inhibiting apoptotic response required for tumor suppression. RUNX family, which is composed of RUNX1, RUNX2, and RUNX3, is a sequence-specific transcription factor and is closely involved in a variety of cellular processes including development, differentiation, and/or tumorigenesis. In this review, we describe a background of p53 and a functional collaboration between p53 and RUNX family in response to DNA damage.


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