Herpes Simplex Virus 1 Alkaline Nuclease Is Required for Efficient Egress of Capsids from the Nucleus

Shao, Lei; Rapp, Lisa; Weller, Sandra K.

doi:10.1006/viro.1993.1463

Cited by 95 publications

(147 citation statements)

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“…However, the viral alkaline nuclease is not required in vivo for transient virus origin-dependent DNA synthesis in the HSV-1, HCMV or EBV systems (Wu et al, 1988 ;Pari & Anders, 1993 ;Fixman et al, 1992). Additionally, the generation of a null mutant in the HSV-1 alkaline nuclease gene UL12 has allowed detailed analysis of the block in virus replication (Weller et al, 1990 ;Shao et al, 1993). The null mutant synthesizes viral DNA at levels approaching those in wild-type infection, but egress of DNA-filled capsids from the nucleus is blocked.…”

Section: Discussionmentioning

confidence: 99%

The human cytomegalovirus UL98 gene encodes the conserved herpesvirus alkaline nuclease.

Sheaffer

Weinheimer

Tenney

1997

Journal of General Virology

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The human cytomegalovirus (HCMV) UL98 gene is predicted to encode a homologue of the conserved herpesvirus alkaline nuclease. To determine if the HCMV UL98 gene product is functionally homologous to other herpesvirus alkaline nucleases, the HCMV UL98 protein was purified and its activity characterized in vitro. Extracts of HCMV-infected cells were fractionated using Q Sepharose, phosphocellulose and native DNA cellulose chromatography. UL98 immunoreactivity copurified with alkaline pH-dependent nuclease activity. The purified protein migrated at its predicted size of approximately 65 kDa in denaturing polyacrylamide gels,

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Section: Discussionmentioning

confidence: 99%

The human cytomegalovirus UL98 gene encodes the conserved herpesvirus alkaline nuclease.

Sheaffer

Weinheimer

Tenney

1997

Journal of General Virology

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“…The previously observed deficiencies in genome replication and packaging exhibited by UL12 null mutants (Martinez et al, 1996b;Porter & Stow, 2004;Shao et al, 1993;Weller et al, 1990) were faithfully recapitulated in a transient assay using the amplicon pSA1. This assay, in turn, provided a means of investigating intermolecular recombination and the requirements for the cis-acting viral packaging signal in the absence of the UL12 product.…”

Section: Discussionmentioning

confidence: 56%

“…The precise role of AN during HSV-1 infection remains incompletely understood. Phenotypic analyses of UL12 null mutants have shown that the observed decrease in virus yield results from the cumulative effect of relatively small reductions in viral DNA synthesis, DNA packaging, capsid egress from the nucleus and the ability of progeny particles to initiate new cycles of infection (Martinez et al, 1996b;Porter & Stow, 2004;Shao et al, 1993;Weller et al, 1990). In addition, analysis of replicating concatemeric DNA suggests that in the absence of AN the replicative intermediates have a more complex structure with an increased frequency of branches (Martinez et al, 1996a), whilst structural abnormalities have also been detected in the genomes of progeny virions (Porter & Stow, 2004).…”

Section: Introductionmentioning

confidence: 99%

Replication, recombination and packaging of amplicon DNA in cells infected with the herpes simplex virus type 1 alkaline nuclease null mutant ambUL12

Porter¹,

Stow²

2004

Journal of General Virology

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The alkaline nuclease (AN) encoded by gene UL12 of herpes simplex virus type 1 (HSV-1) is essential for efficient virus replication but its role during the lytic cycle remains incompletely understood. Inactivation of the UL12 gene results in reductions in viral DNA synthesis, DNA packaging, egress of DNA-containing capsids from the nucleus and ability of progeny virions to initiate new cycles of infection. Mechanistically, AN has been implicated in resolving branched structures in HSV-1 replicative intermediates prior to encapsidation, and promoting DNA strand-exchange. In this study, amplicons (bacterial plasmids containing functional copies of a virus replication origin and packaging signal) were used to analyse further the defects of the UL12 null mutant ambUL12. When ambUL12 was used as a helper virus both replication and packaging of the transfected amplicon were reduced in comparison with cells infected with wild-type (wt) HSV-1, and to extents similar to those previously observed for genomic ambUL12 DNA. By using amplicons differing at a specific restriction endonuclease site it was demonstrated that replicating molecules exhibit high frequency intermolecular recombination in both wt-and mutant-infected cells. Surprisingly, in the absence of the UL12 product, amplicons lacking a functional encapsidation signal were packaged. Moreover, these packaged molecules could be serially propagated indicating that they had been incorporated into functional virions. This difference in packaging specificity between wt HSV-1 and ambUL12 might indicate that replicative intermediates accumulating in the absence of AN contain an increased incidence of structures that can serve for the initiation of DNA packaging.

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“…Analysis of this mutant suggested that DNase is required for the efficient processing of viral DNA replication intermediates and for the egress of capsids from the nucleus but that it is not essential for viral DNA synthesis [10][11][12]. A previous study indicated that PRV DNase could cleave the double-stranded and single-stranded DNA species under alkaline conditions in the presence of Mg# + ions.…”

Section: Introductionmentioning

confidence: 99%

Identification of a DNA-binding domain and an active-site residue of pseudorabies virus DNase

Hsiang

et al. 2000

Biochemical Journal

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The pseudorabies virus (PRV) DNase gene has an open reading frame of 1476 nt, capable of coding a 492-residue protein. A previous study showed that PRV DNase is an alkaline exonuclease and endonuclease, exhibiting an Escherichia coli RecBCD-like catalytic function. To analyse its catalytic mechanism further, we constructed a set of clones truncated at the Nterminus or C-terminus of PRV DNase. The deleted mutants were expressed in E. coli with the use of pET expression vectors, then purified to homogeneity. Our results indicate that (1) the region spanning residues 274-492 exhibits a DNA-binding ability 7-fold that of the intact DNase ; (2) the N-terminal 62 residues and the C-terminal 39 residues have important roles in 3h-exonuclease activity, and (3) residues 63-453 are responsible for 5h-and 3h-exonuclease activities. Further chemical modification

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Herpes Simplex Virus 1 Alkaline Nuclease Is Required for Efficient Egress of Capsids from the Nucleus

Cited by 95 publications

References 0 publications

The human cytomegalovirus UL98 gene encodes the conserved herpesvirus alkaline nuclease.

The human cytomegalovirus UL98 gene encodes the conserved herpesvirus alkaline nuclease.

Replication, recombination and packaging of amplicon DNA in cells infected with the herpes simplex virus type 1 alkaline nuclease null mutant ambUL12

Identification of a DNA-binding domain and an active-site residue of pseudorabies virus DNase

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