scholarly journals Human CAR Gene Expression in Nonpermissive Hamster Cells Boosts Entry of Type 12 Adenovirions and Nuclear Import of Viral DNA

2008 ◽  
Vol 82 (8) ◽  
pp. 4159-4163 ◽  
Author(s):  
Norbert Hochstein ◽  
Dennis Webb ◽  
Marianna Hösel ◽  
Werner Seidel ◽  
Sabrina Auerochs ◽  
...  
Keyword(s):  
Dna Replication ◽  
Nuclear Import ◽  
Cytopathic Effect ◽  
Adenovirus Type ◽  
Velocity Sedimentation ◽  
Viral Dna ◽  
Viral Dna Replication ◽  
Coxsackie And Adenovirus Receptor ◽  
Zone Velocity ◽  
Adenovirus Receptor

ABSTRACT Adenovirus type 12 (Ad12) propagation in hamster BHK21 cells is blocked prior to viral DNA replication. The amounts of Ad12 DNA in the nuclei or cytoplasm of hamster cells are about 2 orders of magnitude (2 h postinfection [p.i.]) and 4 to 5 orders of magnitude (48 h p.i.) lower than in permissive human cells. Cell line BHK21-hCAR is transgenic for and expresses the human coxsackie- and adenovirus receptor (hCAR) gene. Nuclear uptake of Ad12 DNA in BHK21-hCAR cells is markedly increased compared to that in naïve BHK21 cells. Ad12 elicits a cytopathic effect in BHK21-hCAR cells but not in BHK21 cells. Quantitative PCR or [3H]thymidine labeling followed by zone velocity sedimentation fails to detect Ad12 DNA replication in BHK21 or BHK21-hCAR cells. Newly assembled Ad12 virions cannot be detected. Thus, the block in Ad12 DNA replication in hamster cells is not released by enhanced nuclear import of Ad12 DNA.

scholarly journals Cellular Cleavage and Polyadenylation Specificity Factor 6 (CPSF6) Mediates Nuclear Import of Human Bocavirus 1 NP1 Protein and Modulates Viral Capsid Protein Expression

2019 ◽  
Vol 94 (2) ◽  
Author(s):  
Xiaomei Wang ◽  
Peng Xu ◽  
Fang Cheng ◽  
Yi Li ◽  
Zekun Wang ◽  
...  
Keyword(s):  
Dna Replication ◽  
Capsid Protein ◽  
Nuclear Import ◽  
Nonstructural Protein ◽  
Human Bocavirus ◽  
Viral Dna ◽  
Viral Dna Replication ◽  
Specificity Factor ◽  
Tract Infections

ABSTRACT Human bocavirus 1 (HBoV1), which belongs to the genus Bocaparvovirus of the Parvoviridae family, causes acute respiratory tract infections in young children. In vitro, HBoV1 infects polarized primary human airway epithelium (HAE) cultured at an air-liquid interface (HAE-ALI). HBoV1 encodes a small nonstructural protein, nuclear protein 1 (NP1), that plays an essential role in the maturation of capsid protein (VP)-encoding mRNAs and viral DNA replication. In this study, we determined the broad interactome of NP1 using the proximity-dependent biotin identification (BioID) assay combined with mass spectrometry (MS). We confirmed that two host mRNA processing factors, DEAH-box helicase 15 (DHX15) and cleavage and polyadenylation specificity factor 6 (CPSF6; also known as CFIm68), a subunit of the cleavage factor Im complex (CFIm), interact with HBoV1 NP1 independently of any DNA or mRNAs. Knockdown of CPSF6 significantly decreased the expression of capsid protein but not that of DHX15. We further demonstrated that NP1 directly interacts with CPSF6 in vitro and colocalizes within the virus replication centers. Importantly, we revealed a novel role of CPSF6 in the nuclear import of NP1, in addition to the critical role of CPSF6 in NP1-facilitated maturation of VP-encoding mRNAs. Thus, our study suggests that CPSF6 interacts with NP1 to escort NP1 imported into the nucleus for its function in the modulation of viral mRNA processing and viral DNA replication. IMPORTANCE Human bocavirus 1 (HBoV1) is one of the significant pathogens causing acute respiratory tract infections in young children worldwide. HBoV1 encodes a small nonstructural protein (NP1) that plays an important role in the maturation of viral mRNAs encoding capsid proteins as well as in viral DNA replication. Here, we identified a critical host factor, CPSF6, that directly interacts with NP1, mediates the nuclear import of NP1, and plays a role in the maturation of capsid protein-encoding mRNAs in the nucleus. The identification of the direct interaction between viral NP1 and host CPSF6 provides new insights into the mechanism by which a viral small nonstructural protein facilitates the multiple regulation of viral gene expression and replication and reveals a novel target for potent antiviral drug development.

scholarly journals A Lysine Residue Essential for Geminivirus Replication Also Controls Nuclear Localization of the Tomato Yellow Leaf Curl Virus Rep Protein

2019 ◽  
Vol 93 (10) ◽  
Author(s):  
Francesca Maio ◽  
Manuel Arroyo-Mateos ◽  
Benjamin G. Bobay ◽  
Eduardo R. Bejarano ◽  
Marcel Prins ◽  
...  
Keyword(s):  
Dna Replication ◽  
Nuclear Localization ◽  
Nuclear Import ◽  
Tomato Yellow Leaf ◽  
Host Factors ◽  
Yellow Leaf ◽  
Viral Dna ◽  
Viral Dna Replication ◽  
Rep Protein ◽  
Leaf Curl Virus

ABSTRACTGeminiviruses are single-stranded DNA (ssDNA) viruses that infect a wide range of plants. To promote viral replication, geminiviruses manipulate the host cell cycle. The viral protein Rep is essential to reprogram the cell cycle and then initiate viral DNA replication by interacting with a plethora of nuclear host factors. Even though many protein domains of Rep have been characterized, little is known about its nuclear targeting. Here, we show that one conserved lysine in the N-terminal part of Rep is pivotal for nuclear localization of the Rep protein fromTomato yellow leaf curl virus(TYLCV), with two other lysines also contributing to its nuclear import. Previous work had identified that these residues are essential for Rep fromTomato golden mosaic virus(TGMV) to interact with the E2 SUMO-conjugating enzyme (SCE1). We here show that mutating these lysines leads to nuclear exclusion of TYLCV Rep without compromising its interaction with SCE1. Moreover, the ability of TYLCV Rep to promote viral DNA replication also depends on this highly conserved lysine independently of its role in nuclear import of Rep. Our data thus reveal that this lysine potentially has a broad role in geminivirus replication, but its role in nuclear import and SCE1 binding differs depending on the Rep protein examined.IMPORTANCENuclear activity of the replication initiator protein (Rep) of geminiviruses is essential for viral replication. We now define that one highly conserved lysine is important for nuclear import of Rep from three different begomoviruses. To our knowledge, this is the first time that nuclear localization has been mapped for any geminiviral Rep protein. Our data add another key function to this lysine residue, besides its roles in viral DNA replication and interaction with host factors, such as the SUMO E2-conjugating enzyme.

scholarly journals Biology of Ovine Adenovirus Infection of Nonpermissive Cells

2002 ◽  
Vol 76 (21) ◽  
pp. 10882-10893 ◽  
Author(s):  
Daniel Kümin ◽  
Christian Hofmann ◽  
Michael Rudolph ◽  
Gerald W. Both ◽  
Peter Löser
Keyword(s):  
Dna Replication ◽  
Early Stage ◽  
Virus Production ◽  
Adenovirus Type ◽  
Cell Types ◽  
Viral Proteins ◽  
Vector System ◽  
Viral Dna ◽  
Viral Dna Replication ◽  
Wide Range

ABSTRACT Nonhuman adenoviruses, including those of the genus Atadenovirus, have the potential to serve as vectors for vaccine and gene therapy applications in humans, since they are resistant to preexisting immunity induced by human adenoviruses in the majority of the population. In this study, we elucidate the outcome of infection by ovine adenovirus type 7 isolate 287 (OAdV) of several nonovine cell types. We show here that OAdV infects a wide range of nonovine cells but is unable to complete its replication cycle in any of them. In nonovine, nonfibroblast cells, viral replication is blocked at an early stage before the onset of, or early in, DNA replication. Some fibroblasts, on the other hand, allow viral DNA replication but block virus production at a later stage during or after the translation of late viral proteins. Late viral proteins are expressed in cells where viral DNA replication takes place, albeit at a reduced level. Significantly, late proteins are not properly processed, and their cellular distribution differs from that observed in infected ovine cells. Thus, our results clearly show that OAdV infection of all nonovine cells tested is abortive even if significant viral DNA replication occurs. These findings have significant positive implications with respect to the safety of the vector system and its future use in humans.

scholarly journals BGLF4 Kinase Modulates the Structure and Transport Preference of the Nuclear Pore Complex To Facilitate Nuclear Import of Epstein-Barr Virus Lytic Proteins

2014 ◽  
Vol 89 (3) ◽  
pp. 1703-1718 ◽  
Author(s):  
Chou-Wei Chang ◽  
Chung-Pei Lee ◽  
Mei-Tzu Su ◽  
Ching-Hwa Tsai ◽  
Mei-Ru Chen
Keyword(s):  
Dna Replication ◽  
Nuclear Import ◽  
Epstein Barr Virus ◽  
Lytic Replication ◽  
Nuclear Pore ◽  
Nuclear Targeting ◽  
Viral Dna ◽  
Viral Dna Replication ◽  
Barr Virus ◽  
Epstein Barr

ABSTRACTBGLF4 kinase, the only Ser/Thr protein kinase encoded by the Epstein-Barr virus (EBV) genome, phosphorylates multiple viral and cellular substrates to optimize the cellular environment for viral DNA replication and the nuclear egress of nucleocapsids. Previously, we found that nuclear targeting of BGLF4 is through direct interaction with the FG repeat-containing nucleoporins (FG-Nups) Nup62 and Nup153 independently of cytosolic transport factors. Here, we investigated the regulatory effects of BGLF4 on the structure and biological functions of the nuclear pore complex (NPC). In EBV-positive NA cells, the distribution of FG-Nups was modified during EBV reactivation. In transfected cells, BGLF4 changed the staining pattern of Nup62 and Nup153 in a kinase activity-dependent manner. Detection with anti-phospho-Ser/Thr-Pro MPM-2 antibody demonstrated that BGLF4 induced the phosphorylation of Nup62 and Nup153. The nuclear targeting of importin β was attenuated in the presence of BGLF4, leading to inhibition of canonical nuclear localization signal (NLS)-mediated nuclear import. Anin vitronuclear import assay revealed that BGLF4 induced the nuclear import of larger molecules. Notably, we found that BGLF4 promoted the nuclear import of several non-NLS-containing EBV proteins, including the viral DNA-replicating enzymes BSLF1, BBLF2/3, and BBLF4 and the major capsid protein (VCA), in cotransfected cells. The data presented here suggest that BGLF4 interferes with the normal functions of Nup62 and Nup153 and preferentially helps the nuclear import of viral proteins for viral DNA replication and assembly. In addition, the nuclear import-promoting activity was found in cells expressing the BGLF4 homologs of another two gammaherpesviruses but not those from alpha- and betaherpesviruses.IMPORTANCEDuring lytic replication, many EBV genome-encoded proteins need to be transported into the nucleus, not only for viral DNA replication but also for the assembly of nucleocapsids. Because nuclear pore complexes are effective gateways that control nucleocytoplasmic traffic, most EBV proteins without canonical NLSs are retained in the cytoplasm until they form complexes with their NLS-containing partners for nuclear targeting. In this study, we found that EBV BGLF4 protein kinase interacts with the Nup62 and Nup153 and induces the redistribution of FG-Nups. BGLF4 modulates the function of the NPC to inhibit the nuclear import of host NLS-containing proteins. Simultaneously, the nuclear import of non-NLS-containing EBV lytic proteins was enhanced, possibly through phosphorylation of Nup62 and Nup153, nuclear pore dilation, or microtubule reorganization. Overall, our data suggest that BGLF4-induced modification of nuclear pore transport may block nuclear targeting of cellular proteins and increase the import of viral proteins to promote viral lytic replication.

The infection and viral DNA replication ofBocavirusminute virus of canine in permissive cells and non-permissive cells

2010 ◽  
Vol 34 (8) ◽  
pp. S60-S60
Author(s):  
Yuning Sun ◽  
Fang Li ◽  
Jianming Qiu ◽  
Xiaohong Lu
Keyword(s):  
Dna Replication ◽  
Viral Dna ◽  
Viral Dna Replication

scholarly journals Persistent Human Papillomavirus Infection

Viruses ◽  
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.

Sign in / Sign up

Export Citation Format

Share Document