UL84-independent replication of human cytomegalovirus strain TB40/E

Spector, David J.; Yetming, Kristen

doi:10.1016/j.virol.2010.08.029

Cited by 20 publications

(17 citation statements)

References 55 publications

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“…This contrasts with data from Spector and Yetming (45), who found that UL84 is not required for replication of HCMV strain TB40/E. The discrepancies among these studies remain unresolved.…”

Section: Discussioncontrasting

confidence: 68%

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A Mutation Deleting Sequences Encoding the Amino Terminus of Human Cytomegalovirus UL84 Impairs Interaction with UL44 and Capsid Localization

Strang

Bender

Sharma

et al. 2012

J Virol

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Protein-protein interactions are required for many biological functions. Previous work has demonstrated an interaction between the human cytomegalovirus DNA polymerase subunit UL44 and the viral replication factor UL84. In this study, glutathione S-transferase pulldown assays indicated that residues 1 to 68 of UL84 are both necessary and sufficient for efficient interaction of UL84 with UL44 in vitro. We created a mutant virus in which sequences encoding these residues were deleted. This mutant displayed decreased virus replication compared to wild-type virus. Immunoprecipitation assays showed that the mutation decreased but did not abrogate association of UL84 with UL44 in infected cell lysate, suggesting that the association in the infected cell can involve other protein-protein interactions. Most biological processes require protein-protein interactions. We have been studying human cytomegalovirus (HCMV) UL44 with the hypothesis that association of viral and cellular proteins with this protein is required for viral DNA synthesis. UL44 is the presumptive processivity subunit of the HCMV DNA polymerase and shares notable structural homology with the eukaryotic DNA polymerase processivity factor PCNA (3, 4). Multiple proteins required for DNA synthesis and repair associate with PCNA as the need for the function of these proteins arises (31, 32). Based on the structure of UL44 (3) and the interaction of UL44 with the catalytic subunit of the HCMV DNA polymerase UL54 (4), we hypothesized that, like PCNA, UL44 might interact with multiple viral and cellular proteins during viral DNA synthesis (4). In several proteomic studies we catalogued a large number of viral and cellular proteins that associate with UL44 in infected cell lysate (47, 50). These included the cellular protein nucleolin (47) and the viral proteins IRS1, TRS1 (49), and UL84 (47, 50). UL44 has also been found to associate with UL84 in a proteomic screen for interaction partners of UL84 in infected cell lysate (15).UL84 has been described as necessary for virus replication of HCMV laboratory strains AD169 and Towne (13,16,55) and for viral DNA synthesis of AD169 (16). Chromatin immunoprecipitation and proteomic studies have shown that UL84 is present at the viral origin of replication (7,26). It has been reported that UL84 has UTPase activity, and it has been suggested that UL84 functions as a viral origin binding protein (7, 9). However, sequence analysis of UL84 and related proteins indicates that UL84 is more related to dUTPase, not UTPase (11). Additionally, UL84 can interact with the viral transcriptional transactivator IE2 (44), potentially to modulate IE2-mediated transcription (19). Interaction of UL84 with IE2, via amino acids 68 to 105 of UL84 is necessary to maintain UL84 protein levels in the infected cell (37, 38). However, a recent report has indicated that in at least one strain of HCMV (TB40/E), UL84 is not required for viral replication (45).It is unknown what purpose the association of UL44 and UL84 serves in the infected cell and ...

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“…This contrasts with data from Spector and Yetming (45), who found that UL84 is not required for replication of HCMV strain TB40/E. The discrepancies among these studies remain unresolved.…”

Section: Discussioncontrasting

confidence: 68%

“…Interaction of UL84 with IE2, via amino acids 68 to 105 of UL84 is necessary to maintain UL84 protein levels in the infected cell (37,38). However, a recent report has indicated that in at least one strain of HCMV (TB40/E), UL84 is not required for viral replication (45).…”

mentioning

confidence: 99%

A Mutation Deleting Sequences Encoding the Amino Terminus of Human Cytomegalovirus UL84 Impairs Interaction with UL44 and Capsid Localization

Strang

Bender

Sharma

et al. 2012

J Virol

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“…HCMV does not encode a de facto origin binding protein, so the exact mechanism by which it initiates viral lytic DNA replication is unclear. Although, recently, it has been shown that HCMV UL84 can interact with the viral origin of replication and may function as a replication initiator via interactions with C/EBP [38], [48] [49], other work has shown that UL84 is dispensible for HCMV lytic replication [50]. Consequently, we have analysed whether initiation of HCMV DNA replication involves host cell pre-RC factors.…”

Section: Discussionmentioning

confidence: 99%

Depletion of Cellular Pre-Replication Complex Factors Results in Increased Human Cytomegalovirus DNA Replication

Braun

Poole

2012

PLoS ONE

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Although HCMV encodes many genes required for the replication of its DNA genome, no HCMV-encoded orthologue of the origin binding protein, which has been identified in other herpesviruses, has been identified. This has led to speculation that HCMV may use other viral proteins or possibly cellular factors for the initiation of DNA synthesis. It is also unclear whether cellular replication factors are required for efficient replication of viral DNA during or after viral replication origin recognition. Consequently, we have asked whether cellular pre-replication (pre-RC) factors that are either initially associated with cellular origin of replication (e.g. ORC2), those which recruit other replication factors (e.g. Cdt1 or Cdc6) or those which are subsequently recruited (e.g. MCMs) play any role in the HCMV DNA replication. We show that whilst RNAi-mediated knock-down of these factors in the cell affects cellular DNA replication, as predicted, it results in concomitant increases in viral DNA replication. These data show that cellular factors which initiate cellular DNA synthesis are not required for the initiation of replication of viral DNA and suggest that inhibition of cellular DNA synthesis, in itself, fosters conditions which are conducive to viral DNA replication.

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“…To determine whether only the latently infected cells are responsible for the production of these cytokines or whether bystander cells in the population culture are also induced to express these cytokines, we analyzed the expression of cIL-10 and TGF-β in uninfected bystander in the latently infected cells population. CD34 + cells were infected with an isolate of HCMV TB40E (TB40GFP), which expresses GFP under the control of the SV40 origin/promoter cassette (25) and allows expression of GFP in infected undifferentiated myeloid cells (26). Forty-eight hours postinfection, cIL-10 and TGF-β expression was analyzed by intracellular cytokine staining.…”

Section: Intracellular Cytokine Staining Shows That the Latent Secretomementioning

confidence: 99%

Human cytomegalovirus latency alters the cellular secretome, inducing cluster of differentiation (CD)4⁺T-cell migration and suppression of effector function

Mason

Poole

Sissons

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

118

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After primary infection, human cytomegalovirus (HCMV) persists as a life-long latent infection, with host immunosuppression often resulting in clinical reactivation. During lytic infection, major changes in the expression of secreted cellular proteins (the secretome) occur that have profound effects on host–cell interactions, particularly at the level of the host immune response. In contrast, little is known about changes in the secretome that accompany latent infection, yet this is likely to be of major importance for the life-long carriage of this persistent human pathogen in the face of constant immunosurveillance. We have analyzed the secretome of cells carrying latent HCMV and have identified changes in several secreted cellular proteins known to be involved in regulation of the immune response and chemoattraction. Here, we show that a latency-associated increase in CC chemokine ligand (CCL)8 results in the recruitment of cluster of differentiation (CD)4 + T cells to supernatants from latently infected CD34 + cells but that these latent supernatants, also rich in immunosuppressive factors, inhibit cytokine secretion and cytotoxicity of HCMV-specific T-helper (Th)1 CD4 + T cells. These results identify a strategy by which sites of latent HCMV can firstly recruit CD4 + T cells and then inhibit their antiviral effector functions, thereby aiding the maintenance of latent infection in the face of the host immune response.

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UL84-independent replication of human cytomegalovirus strain TB40/E

Cited by 20 publications

References 55 publications

A Mutation Deleting Sequences Encoding the Amino Terminus of Human Cytomegalovirus UL84 Impairs Interaction with UL44 and Capsid Localization

A Mutation Deleting Sequences Encoding the Amino Terminus of Human Cytomegalovirus UL84 Impairs Interaction with UL44 and Capsid Localization

Depletion of Cellular Pre-Replication Complex Factors Results in Increased Human Cytomegalovirus DNA Replication

Human cytomegalovirus latency alters the cellular secretome, inducing cluster of differentiation (CD)4⁺T-cell migration and suppression of effector function

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UL84-independent replication of human cytomegalovirus strain TB40/E

Cited by 20 publications

References 55 publications

A Mutation Deleting Sequences Encoding the Amino Terminus of Human Cytomegalovirus UL84 Impairs Interaction with UL44 and Capsid Localization

A Mutation Deleting Sequences Encoding the Amino Terminus of Human Cytomegalovirus UL84 Impairs Interaction with UL44 and Capsid Localization

Depletion of Cellular Pre-Replication Complex Factors Results in Increased Human Cytomegalovirus DNA Replication

Human cytomegalovirus latency alters the cellular secretome, inducing cluster of differentiation (CD)4+T-cell migration and suppression of effector function

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Human cytomegalovirus latency alters the cellular secretome, inducing cluster of differentiation (CD)4⁺T-cell migration and suppression of effector function