scholarly journals Role for the Adenovirus IVa2 Protein in Packaging of Viral DNA

2001 ◽  
Vol 75 (21) ◽  
pp. 10446-10454 ◽  
Author(s):  
Wei Zhang ◽  
Jonathan A. Low ◽  
Joan B. Christensen ◽  
Michael J. Imperiale
Keyword(s):  
Gene Transfer ◽  
Direct Evidence ◽  
Helper Virus ◽  
Dna Packaging ◽  
Chimeric Virus ◽  
Viral Dna ◽  
293 Cells ◽  
Inverted Terminal Repeats ◽  
Viral Dna Packaging ◽  
Packaging Sequence

ABSTRACT Although it has been demonstrated that the adenovirus IVa2 protein binds to the packaging domains on the viral chromosome and interacts with the viral L1 52/55-kDa protein, which is required for viral DNA packaging, there has been no direct evidence demonstrating that the IVa2 protein is involved in DNA packaging. To understand in greater detail the DNA packaging mechanisms of adenovirus, we have asked whether DNA packaging is serotype or subgroup specific. We found that Ad7 (subgroup B), Ad12 (subgroup A), and Ad17 (subgroup D) cannot complement the defect of an Ad5 (subgroup C) mutant,pm8001, which does not package its DNA due to a mutation in the L1 52/55-kDa gene. This indicates that the DNA packaging systems of different serotypes cannot interact productively with Ad5 DNA. Based on this, a chimeric virus containing the Ad7 genome except for the inverted terminal repeats and packaging sequence from Ad5 was constructed. This chimeric virus replicates its DNA and synthesizes Ad7 proteins, but it cannot package its DNA in 293 cells or 293 cells expressing the Ad5 L1 52/55-kDa protein. However, this chimeric virus packages its DNA in 293 cells expressing the Ad5 IVa2 protein. These results indicate that the IVa2 protein plays a role in viral DNA packaging and that its function is serotype specific. Since this chimeric virus cannot package its own DNA, but produces all the components for packaging Ad7 DNA, it may be a more suitable helper virus for the growth of Ad7 gutted vectors for gene transfer.

Interaction of the adenoviral IVa2 protein with a truncated viral DNA packaging sequence

2009 ◽  
Vol 140 (1-3) ◽  
pp. 78-90 ◽  
Author(s):  
Teng-Chieh Yang ◽  
Qin Yang ◽  
Nasib Karl Maluf
Keyword(s):  
Dna Packaging ◽  
Viral Dna ◽  
Viral Dna Packaging ◽  
Packaging Sequence

scholarly journals Defective Infectious Particles and Rare Packaged Genomes Produced by Cells Carrying Terminal-Repeat-Negative Epstein-Barr Virus

2005 ◽  
Vol 79 (12) ◽  
pp. 7641-7647 ◽  
Author(s):  
R. Feederle ◽  
C. Shannon-Lowe ◽  
G. Baldwin ◽  
H. J. Delecluse
Keyword(s):  
Epstein Barr Virus ◽  
Virus Production ◽  
Dna Packaging ◽  
Target Cells ◽  
Viral Dna ◽  
Barr Virus ◽  
293 Cells ◽  
Viral Mutant ◽  
Epstein Barr ◽  
Viral Dna Packaging

ABSTRACT The Epstein-Barr virus (EBV) lytic program includes lytic viral DNA replication and the production of a viral particle into which the replicated viral DNA is packaged. The terminal repeats (TRs) located at the end of the linear viral DNA have been identified as the packaging signals. A TR-negative (TR−) mutant therefore provides an appropriate tool to analyze the relationships between EBV DNA packaging and virus production. Here, we show that supernatants from lytically induced 293 cells carrying TR mutant EBV genomes (293/TR−) contain large amounts of viral particles devoid of viral DNA which are nevertheless able to bind to EBV target cells. This shows that viral DNA packaging is not a prerequisite for virion formation and egress. Rather surprisingly, supernatants from lytically induced 293/TR− cells also contained rare infectious viruses carrying the viral mutant DNA. This observation indicates that the TRs are important but not absolutely essential for virus encapsidation.

scholarly journals Requirement of the Adenovirus IVa2 Protein for Virus Assembly

2003 ◽  
Vol 77 (6) ◽  
pp. 3586-3594 ◽  
Author(s):  
Wei Zhang ◽  
Michael J. Imperiale
Keyword(s):  
Virus Assembly ◽  
Dna Packaging ◽  
Mutant Virus ◽  
Wild Type Virus ◽  
Wild Type ◽  
Electron Microscopic ◽  
Viral Dna ◽  
293 Cells ◽  
Viral Particles ◽  
Viral Dna Packaging

ABSTRACT The adenovirus L1 52/55-kDa protein is required for viral DNA packaging and interacts with the viral IVa2 protein, which binds to the viral packaging sequence. Previous reports suggest that the IVa2 protein plays a role in viral DNA packaging and that this function of the IVa2 protein is serotype specific. To further examine the function of the IVa2 protein in viral DNA packaging, a mutant virus that does not express the IVa2 protein was constructed by introducing two stop codons at the beginning of the IVa2 open reading frame in a full-length bacterial clone of adenovirus type 5. The mutant virus, pm8002, was defective for growth in 293 cells, although it replicated its DNA and produced early and late viral proteins. Electron microscopic and gradient analyses revealed that the mutant virus did not assemble any viral particles in 293 cells. In 293-IVa2 cells, which express the IVa2 protein, infectious viruses were produced, although the titer of the mutant virus was lower than that of the wild-type virus, indicating that these cells may not fully complement the mutation. The mutant viral particles produced in 293-IVa2 cells were heterogeneous in size and shape, less stable, and did not traffic efficiently to the nucleus. Marker rescue experiments with a wild-type IVa2 DNA fragment confirmed that the only mutations present in pm8002 were in the IVa2 gene. The results indicate that the IVa2 protein is required for adenovirus assembly and suggest that virus particles may be assembled around the DNA rather than DNA being packaged into preformed capsids.

scholarly journals Phylogenetic evidence of headful packaging strategy in gene transfer agents

2020 ◽  
Author(s):  
Emma Esterman ◽  
Yuri I. Wolf ◽  
Roman Kogay ◽  
Eugene V. Koonin ◽  
Olga Zhaxybayeva
Keyword(s):  
Gene Transfer ◽  
Rhodobacter Capsulatus ◽  
Large Subunit ◽  
Dna Packaging ◽  
Host Genome ◽  
Bacterial And Archaeal Communities ◽  
History Of ◽  
Viral Dna Packaging ◽  
Packaging Strategy ◽  
Transfer Agents

AbstractGene transfer agents (GTAs) are virus-like particles encoded and produced by many bacteria and archaea. Unlike viruses, GTAs package fragments of the host genome instead of the genes that encode the components of the GTA itself. As a result of this non-specific DNA packaging, GTAs can transfer genes within bacterial and archaeal communities. GTAs clearly evolved from viruses and are thought to have been maintained in prokaryotic genomes due to the advantages associated with their DNA transfer capacity. The most-studied GTA is produced by the alphaproteobacterium Rhodobacter capsulatus (RcGTA), which packages random portions of the host genome at a lower DNA density than usually observed in tailed bacterial viruses. How the DNA packaging properties of RcGTA evolved from those of the ancestral virus remains unknown. To address this question, we reconstructed the evolutionary history of the large subunit of the terminase (TerL), a highly conserved enzyme used by viruses and GTAs to package DNA. We found that RcGTA-like TerLs grouped within viruses that employ the headful packaging strategy. Because distinct mechanisms of viral DNA packaging correspond to differences in the TerL amino acid sequence, our finding suggests that RcGTA evolved from a headful packaging virus. Headful packaging is the least sequence-specific mode of DNA packaging, which would facilitate the switch from packaging of the viral genome to packaging random pieces of the host genome during GTA evolution.

Translation of the long-term fundamental studies on viral DNA packaging motors into nanotechnology and nanomedicine

2020 ◽  
Vol 63 (8) ◽  
pp. 1103-1129 ◽  
Author(s):  
Chenxi Liang ◽  
Tao Weitao ◽  
Lixia Zhou ◽  
Peixuan Guo
Keyword(s):  
Dna Packaging ◽  
Viral Dna ◽  
Viral Dna Packaging
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