Productive herpesvirus lytic replication in primary effusion lymphoma cells requires S-phase entry

Gammaherpesviruses establish lifelong latent infection in B lymphocytes and are the causative agent of several B-cell malignancies and lymphoproliferative disorders. While a quiescent latent infection allows these pathogens to evade immune detection, initiation of an alternative lifecycle stage, known as lytic replication, is an essential step in the production and dissemination of infectious progeny. Although cessation of cellular proliferation is an eventual consequence of lytic induction, exactly how gammaherpesviruses manipulate the cell cycle prior to amplification of viral DNA remains under debate. Here we show that the onset of Kaposi's sarcoma-associated herpesvirus (KSHV) lytic reactivation in B cells leads to S-phase accumulation and that exit from G1 is required for efficient viral DNA replication. We also show that lytic replication leads to an S-phase-specific activation of the DNA damage response (DDR) that is abrogated when lytic replication is restricted to G0/G1. Finally, we observe that expression of early lytic viral genes results in cellular replication stress with increased stalling of DNA replication forks. Overall, we demonstrate that S-phase entry is important for optimal KSHV replication, that G1 arresting compounds are effective inhibitors of viral propagation, and that lytic-induced cell-cycle arrest could occur through the obstruction of cellular replication forks and subsequent activation of the DDR.

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Human Parvovirus B19 Infection Causes Cell Cycle Arrest of Human Erythroid Progenitors at Late S Phase That Favors Viral DNA Replication

Journal of Virology ◽

10.1128/jvi.02333-13 ◽

2013 ◽

Vol 87 (23) ◽

pp. 12766-12775 ◽

Cited By ~ 34

Author(s):

Yong Luo ◽

Steve Kleiboeker ◽

Xuefeng Deng ◽

Jianming Qiu

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Dna Content ◽

Parvovirus B19 ◽

S Phase ◽

Human Parvovirus B19 ◽

Viral Dna ◽

Viral Dna Replication ◽

Cycle Arrest ◽

Cellular Dna

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.

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Mitotic replisome disassembly in vertebrates

10.1101/418368 ◽

2018 ◽

Author(s):

Sara Priego Moreno ◽

Rebecca M. Jones ◽

Divyasree Poovathumkadavil ◽

Agnieszka Gambus

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Ubiquitin Ligase ◽

S Phase ◽

Replication Forks ◽

Replication Machinery ◽

Replicative Helicase ◽

Egg Extract ◽

Eukaryotic Dna ◽

Higher Eukaryotes

ABSTRACTRecent years have brought a breakthrough in our understanding of the process of eukaryotic DNA replication termination. We have shown that the process of replication machinery (replisome) disassembly at the termination of DNA replication forks in S-phase of the cell cycle is driven through polyubiquitylation of one of the replicative helicase subunits Mcm7. Our previous work in C.elegans embryos suggested also an existence of a back-up pathway of replisome disassembly in mitosis. Here we show, that in Xenopus laevis egg extract, any replisome retained on chromatin after S-phase is indeed removed from chromatin in mitosis. This mitotic disassembly pathway depends on formation of K6 and K63 ubiquitin chains on Mcm7 by TRAIP ubiquitin ligase and activity of p97/VCP protein segregase. The mitotic replisome pathway is therefore conserved through evolution in higher eukaryotes. However, unlike in lower eukaryotes it does not require SUMO modifications. This process can also remove any helicases from chromatin, including “active” stalled ones, indicating a much wider application of this pathway than just a “back-up” for terminated helicases.

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Architecture of Replication Compartments Formed during Epstein-Barr Virus Lytic Replication

Journal of Virology ◽

10.1128/jvi.79.6.3409-3418.2005 ◽

2005 ◽

Vol 79 (6) ◽

pp. 3409-3418 ◽

Cited By ~ 61

Author(s):

Tohru Daikoku ◽

Ayumi Kudoh ◽

Masatoshi Fujita ◽

Yutaka Sugaya ◽

Hiroki Isomura ◽

...

Keyword(s):

Dna Replication ◽

Viral Replication ◽

Epstein Barr Virus ◽

Protein A ◽

Lytic Replication ◽

Viral Dna ◽

Barr Virus ◽

Epstein Barr ◽

Cellular Replication ◽

Cellular Dna

ABSTRACT Epstein-Barr virus (EBV) productive DNA replication occurs at discrete sites, called replication compartments, in nuclei. In this study we performed comprehensive analyses of the architecture of the replication compartments. The BZLF1 oriLyt binding proteins showed a fine, diffuse pattern of distribution throughout the nuclei at immediate-early stages of induction and then became associated with the replicating EBV genome in the replication compartments during lytic infection. The BMRF1 polymerase (Pol) processivity factor showed a homogenous, not dot-like, distribution in the replication compartments, which completely coincided with the newly synthesized viral DNA. Inhibition of viral DNA replication with phosphonoacetic acid, a viral DNA Pol inhibitor, eliminated the DNA-bound form of the BMRF1 protein, although the protein was sufficiently expressed in the cells. These observations together with the findings that almost all abundantly expressed BMRF1 proteins existed in the DNA-bound form suggest that the BMRF1 proteins not only act at viral replication forks as Pol processive factors but also widely distribute on newly replicated EBV genomic DNA. In contrast, the BALF5 Pol catalytic protein, the BALF2 single-stranded-DNA binding protein, and the BBLF2/3 protein, a component of the helicase-primase complex, were colocalized as distinct dots distributed within replication compartments, representing viral replication factories. Whereas cellular replication factories are constructed based on nonchromatin nuclear structures and nuclear matrix, viral replication factories were easily solubilized by DNase I treatment. Thus, compared with cellular DNA replication, EBV lytic DNA replication factories would be simpler so that construction of the replication domain would be more relaxed.

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Reactivation of Lytic Replication from B Cells Latently Infected with Epstein-Barr Virus Occurs with High S-Phase Cyclin-Dependent Kinase Activity while Inhibiting Cellular DNA Replication

Journal of Virology ◽

10.1128/jvi.77.2.851-861.2003 ◽

2003 ◽

Vol 77 (2) ◽

pp. 851-861 ◽

Cited By ~ 69

Author(s):

Ayumi Kudoh ◽

Masatoshi Fujita ◽

Tohru Kiyono ◽

Kiyotaka Kuzushima ◽

Yutaka Sugaya ◽

...

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Epstein Barr Virus ◽

S Phase ◽

Lytic Replication ◽

Cdk Inhibitors ◽

Cyclin Dependent Kinase ◽

Barr Virus ◽

Epstein Barr ◽

Cellular Dna

ABSTRACT Productive infection and replication of herpesviruses usually occurs in growth-arrested cells, but there has been no direct evidence in the case of Epstein-Barr virus (EBV), since an efficient lytic replication system without external stimuli does not exist for the virus. Expression of the EBV lytic-switch transactivator BZLF1 protein in EBV-negative epithelial tumor cell lines, however, is known to arrest the cell cycle in G0/G1 by induction of the tumor suppressor protein p53 and the cyclin-dependent kinase (CDK) inhibitors p21WAF-1/CIP-1 and p27KIP-1, followed by the accumulation of a hypophosphorylated form of the Rb protein. In order to determine the effect of the onset of lytic viral replication on cellular events in latently EBV-infected B LCLs, a tightly controlled induction system of the EBV lytic-replication program by inducible BZLF1 protein expression was established in B95-8 cells. The induction of lytic replication completely arrested cell cycle progression and cellular DNA replication. Surprisingly, the levels of p53, p21WAF-1/CIP-1, and p27KIP-1 were constant before and after induction of the lytic program, indicating that the cell cycle arrest induced by the lytic program is not mediated through p53 and the CDK inhibitors. Furthermore, although cellular DNA replication was blocked, elevation of cyclin E/A expression and accumulation of hyperphosphorylated forms of Rb protein were observed, a post-G1/S phase characteristic of cells. Thus, while the EBV lytic program promoted specific cell cycle-associated activities involved in the progression from G1 to S phase, it inhibited cellular DNA synthesis. Such cellular conditions appear to especially favor viral lytic replication.

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Phosphorylation of the Cyclin-Dependent Kinase Inhibitor p21Cip1 on Serine 130 Is Essential for Viral Cyclin-Mediated Bypass of a p21Cip1-Imposed G1 Arrest

Molecular and Cellular Biology ◽

10.1128/mcb.26.6.2430-2440.2006 ◽

2006 ◽

Vol 26 (6) ◽

pp. 2430-2440 ◽

Cited By ~ 34

Author(s):

Annika Järviluoma ◽

Emma S. Child ◽

Grzegorz Sarek ◽

Papinya Sirimongkolkasem ◽

Gordon Peters ◽

...

Keyword(s):

Cell Cycle ◽

Kinase Inhibitor ◽

Primary Effusion Lymphoma ◽

S Phase ◽

G1 Arrest ◽

Cyclin Dependent Kinase ◽

Partial Restoration ◽

Viral Cyclin ◽

Phase Entry

ABSTRACT K cyclin encoded by Kaposi's sarcoma-associated herpesvirus confers resistance to the cyclin-dependent kinase (cdk) inhibitors p16Ink4A, p21Cip1, and p27Kip1 on the associated cdk6. We have previously shown that K cyclin expression enforces S-phase entry on cells overexpressing p27Kip1 by promoting phosphorylation of p27Kip1 on threonine 187, triggering p27Kip1 down-regulation. Since p21Cip1 acts in a manner similar to that of p27Kip1, we have investigated the subversion of a p21Cip1-induced G1 arrest by K cyclin. Here, we show that p21Cip1 is associated with K cyclin both in overexpression models and in primary effusion lymphoma cells and is a substrate of the K cyclin/cdk6 complex, resulting in phosphorylation of p21Cip1 on serine 130. This phosphoform of p21Cip1 appeared unable to associate with cdk2 in vivo. We further demonstrate that phosphorylation on serine 130 is essential for K cyclin-mediated release of a p21Cip1-imposed G1 arrest. Moreover, we show that under physiological conditions of cell cycle arrest due to elevated levels of p21Cip1 resulting from oxidative stress, K cyclin expression enabled S-phase entry and was associated with p21Cip1 phosphorylation and partial restoration of cdk2 kinase activity. Thus, expression of the viral cyclin enables cells to subvert the cell cycle inhibitory function of p21Cip1 by promoting cdk6-dependent phosphorylation of this antiproliferative protein.

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The Epstein-Barr Virus Protein BRLF1 Activates S Phase Entry through E2F1 Induction

Journal of Virology ◽

10.1128/jvi.73.8.6540-6550.1999 ◽

1999 ◽

Vol 73 (8) ◽

pp. 6540-6550 ◽

Cited By ~ 40

Author(s):

Jennifer J. Swenson ◽

Amy E. Mauser ◽

William K. Kaufmann ◽

Shannon C. Kenney

Keyword(s):

Cell Cycle ◽

Epstein Barr Virus ◽

Human Fibroblasts ◽

S Phase ◽

Lytic Replication ◽

Osteosarcoma Cell ◽

Barr Virus ◽

Infected Cells ◽

Epstein Barr ◽

Phase Entry

ABSTRACT The Epstein-Barr Virus (EBV) immediate-early protein BRLF1 is one of two transactivators which mediate the switch from latent to lytic replication in EBV-infected cells. DNA viruses often modulate the function of critical cell cycle proteins to maximize the efficiency of virus replication. Here we have examined the effect of BRLF1 on cell cycle progression. A replication-deficient adenovirus expressing BRLF1 (AdBRLF1) was used to infect normal human fibroblasts and various epithelial cell lines. BRLF1 expression induced S phase entry in contact-inhibited fibroblasts and in the human osteosarcoma cell line U-2 OS. AdBRLF1 infection produced a dramatic increase in the level of E2F1 but not E2F4. In contrast, the levels of Rb, p107, and p130 were decreased in AdBRLF1-infected cells. Electrophoretic mobility shift assays confirmed an increased level of free E2F1 in the AdBRLF1-infected human fibroblasts. Consistent with the previously described effect of E2F1, AdBRLF1-infected fibroblasts had increased levels of p53 and p21 and died by apoptosis. BRLF1-induced activation of E2F1 may be required for efficient EBV lytic replication, since at least one critical viral replication gene (the viral DNA polymerase) is activated by E2F (C. Liu, N. D. Sista, and J. S. Pagano, J. Virol. 70:2545–2555, 1996).

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Human cytomegalovirus RNA2.7 regulates host cell cycle and facilitates viral DNA replication by inhibiting RNA polymerase II phosphorylation

10.1101/378083 ◽

2018 ◽

Author(s):

Yujing Huang ◽

Jing Zhang ◽

Xin Guo ◽

Qing Wang ◽

Zhongyang Liu ◽

...

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Rna Polymerase ◽

Rna Polymerase Ii ◽

Human Cytomegalovirus ◽

Cell Cycle Control ◽

S Phase ◽

Viral Dna ◽

Viral Dna Replication ◽

Pol Ii

AbstractHuman cytomegalovirus (HCMV) is a ubiquitous pathogen belongs to the beta herpesvirus family. RNA2.7 is a viral long non-coding RNA accounting for more than 20% of total viral transcripts at early time of infection. By construction of RNA2.7 deleted mutant and genome transcriptomic analysis, RNA2.7 is demonstrated to repress host cellular RNA polymerase II (Pol II)-dependent transcription through inhibiting the phosphorylation of RNA polymerase II (Pol II). Co-immunoprecipitation, RNA immunoprecipitation and RNA electrophoretic mobility shift assay are followed to investigate its mechnism. A 145nt-in-length fragment in RNA2.7 is identified to bind to Pol II and block the interaction between Pol II and phosphorylated cyckin-dependent kinase 9 (phospho-CDK9). By inhibiting Pol II phosphorylation, RNA2.7 decreases the transcription and expression levels of chromatin licensing and DNA replication factor 1 (Cdt1) and cell division cycle gene 6 (Cdc6). Through above way, RNA2.7 prevents the entry of cells into S phase and facilitates viral DNA replication. Our results discover the functions of HCMV RNA2.7 in regulation of Pol II phosphorylation and cell cycle control during infection.Author summaryHuman cytomegalovirus (HCMV) RNA2.7 is a viral lncRNA that is most abundant during infection. Here we show that a 145nt-in-length fragment in RNA2.7 binds to RNA polymerase II (Pol II) and blocks the interaction between Pol II and phosphorylated cyckin-dependent kinase 9 (phospho-CDK9). By inhibiting Pol II phosphorylation, RNA2.7 decreases the transcription and expression levels of chromatin licensing and DNA replication factor 1 (Cdt1) and cell division cycle gene 6 (Cdc6), and blocks host cells entering into S phase. RNA2.7 is confirmed to facilitate viral DNA replication through decreasing Cdt1 and Cdc6. Therefore, our results discover the functions of HCMV RNA2.7 in regulation of Pol II phosphorylation and cell cycle control during infection.

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Persistent Human Papillomavirus Infection

Viruses ◽

10.3390/v13020321 ◽

2021 ◽

Vol 13 (2) ◽

pp. 321

Author(s):

Ashley N. Della Fera ◽

Alix Warburton ◽

Tami L. Coursey ◽

Simran Khurana ◽

Alison A. McBride

Keyword(s):

Human Papillomavirus ◽

Dna Replication ◽

Cellular Proliferation ◽

Basal Cells ◽

Viral Dna ◽

Viral Dna Replication ◽

Viral Genomes ◽

Cellular Environment ◽

E6 And E7 ◽

Cellular Replication

Persistent infection with oncogenic human papillomavirus (HPV) types is responsible for ~5% of human cancers. The HPV infectious cycle can sustain long-term infection in stratified epithelia because viral DNA is maintained as low copy number extrachromosomal plasmids in the dividing basal cells of a lesion, while progeny viral genomes are amplified to large numbers in differentiated superficial cells. The viral E1 and E2 proteins initiate viral DNA replication and maintain and partition viral genomes, in concert with the cellular replication machinery. Additionally, the E5, E6, and E7 proteins are required to evade host immune responses and to produce a cellular environment that supports viral DNA replication. An unfortunate consequence of the manipulation of cellular proliferation and differentiation is that cells become at high risk for carcinogenesis.

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Regulation of DNA Replication Licensing and Re-Replication by Cdt1

International Journal of Molecular Sciences ◽

10.3390/ijms22105195 ◽

2021 ◽

Vol 22 (10) ◽

pp. 5195

Author(s):

Hui Zhang

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Dna Replication ◽

Genome Stability ◽

E3 Ligase ◽

S Phase ◽

Replication Initiation ◽

Nuclear Antigen ◽

Repair Synthesis ◽

Ubiquitin E3 Ligase

In eukaryotic cells, DNA replication licensing is precisely regulated to ensure that the initiation of genomic DNA replication in S phase occurs once and only once for each mitotic cell division. A key regulatory mechanism by which DNA re-replication is suppressed is the S phase-dependent proteolysis of Cdt1, an essential replication protein for licensing DNA replication origins by loading the Mcm2-7 replication helicase for DNA duplication in S phase. Cdt1 degradation is mediated by CRL4Cdt2 ubiquitin E3 ligase, which further requires Cdt1 binding to proliferating cell nuclear antigen (PCNA) through a PIP box domain in Cdt1 during DNA synthesis. Recent studies found that Cdt2, the specific subunit of CRL4Cdt2 ubiquitin E3 ligase that targets Cdt1 for degradation, also contains an evolutionarily conserved PIP box-like domain that mediates the interaction with PCNA. These findings suggest that the initiation and elongation of DNA replication or DNA damage-induced repair synthesis provide a novel mechanism by which Cdt1 and CRL4Cdt2 are both recruited onto the trimeric PCNA clamp encircling the replicating DNA strands to promote the interaction between Cdt1 and CRL4Cdt2. The proximity of PCNA-bound Cdt1 to CRL4Cdt2 facilitates the destruction of Cdt1 in response to DNA damage or after DNA replication initiation to prevent DNA re-replication in the cell cycle. CRL4Cdt2 ubiquitin E3 ligase may also regulate the degradation of other PIP box-containing proteins, such as CDK inhibitor p21 and histone methylase Set8, to regulate DNA replication licensing, cell cycle progression, DNA repair, and genome stability by directly interacting with PCNA during DNA replication and repair synthesis.

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Cdc6p establishes and maintains a state of replication competence during G1 phase

Journal of Cell Science ◽

10.1242/jcs.110.6.753 ◽

1997 ◽

Vol 110 (6) ◽

pp. 753-763 ◽

Cited By ~ 1

Author(s):

C.S. Detweiler ◽

J.J. Li

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Transcriptional Repression ◽

Prolonged Exposure ◽

S Phase ◽

Restrictive Temperature ◽

Yeast Saccharomyces Cerevisiae ◽

Important Intermediate ◽

Initiation Of Dna Replication ◽

And Function

CDC6 is essential for the initiation of DNA replication in the budding yeast Saccharomyces cerevisiae. Here we examine the timing of Cdc6p expression and function during the cell cycle. Cdc6p is expressed primarily between mitosis and Start. This pattern of expression is due in part to posttranscriptional controls, since it is maintained when CDC6 is driven by a constitutively induced promoter. Transcriptional repression of CDC6 or exposure of cdc6-1(ts) cells to the restrictive temperature at mitosis blocks subsequent S phase, demonstrating that the activity of newly synthesized Cdc6p is required each cell cycle for DNA replication. In contrast, similar perturbations imposed on cells arrested in G(1) before Start have moderate or no effects on DNA replication. This suggests that, between mitosis and Start, Cdc6p functions in an early step of initiation, effectively making cells competent for replication. Prolonged exposure of cdc6-1(ts) cells to the restrictive temperature at the pre-Start arrest eventually does cripple S phase, indicating that Cdc6p also functions to maintain this initiation competence during G(1). The requirement for Cdc6p to establish and maintain initiation competence tightly correlates with the requirement for Cdc6p to establish and maintain the pre-replicative complex at a replication origin, strongly suggesting that the pre-replicative complex is an important intermediate for the initiation of DNA replication. Confining assembly of the complex to G(1) by restricting expression of Cdc6p to this period may be one way of ensuring precisely one round of replication per cell cycle.

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