Herpes Simplex Virus Type 1/Adeno-Associated Virus Hybrids as Site-Specific Integrating Vectors

ABSTRACT Adeno-associated virus (AAV) is a human parvovirus that replicates only in cells coinfected with a helper virus, such as adenovirus or herpes simplex virus type 1 (HSV-1). We previously showed that nine HSV-1 factors are able to support AAV rep gene expression and genome replication. To elucidate the strategy of AAV replication in the presence of HSV-1, we undertook a proteomic analysis of cellular and HSV-1 factors associated with Rep proteins and thus potentially recruited within AAV replication compartments (AAV RCs). This study resulted in the identification of approximately 60 cellular proteins, among which factors involved in DNA and RNA metabolism represented the largest functional categories. Validation analyses indicated that the cellular DNA replication enzymes RPA, RFC, and PCNA were recruited within HSV-1-induced AAV RCs. Polymerase δ was not identified but subsequently was shown to colocalize with Rep within AAV RCs even in the presence of the HSV-1 polymerase complex. In addition, we found that AAV replication is associated with the recruitment of components of the Mre11/Rad50/Nbs1 complex, Ku70 and -86, and the mismatch repair proteins MSH2, -3, and -6. Finally, several HSV-1 factors were also found to be associated with Rep, including UL12. We demonstrated for the first time that this protein plays a role during AAV replication by enhancing the resolution of AAV replicative forms and AAV particle production. Altogether, these analyses provide the basis to understand how AAV adapts its replication strategy to the nuclear environment induced by the helper virus.

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Herpes Simplex Virus Type 1 Co-Infection Modifies Adeno-Associated Virus Genome End Recombination

Journal of Virology ◽

10.1128/jvi.00486-21 ◽

2021 ◽

Author(s):

Anita Felicitas Meier ◽

Kurt Tobler ◽

Kevin Michaelsen ◽

Bernd Vogt ◽

Els Henckaerts ◽

...

Keyword(s):

Herpes Simplex Virus ◽

Herpes Simplex ◽

Virus Type ◽

Herpes Simplex Virus Type ◽

Molecular Structures ◽

Adeno Associated Virus ◽

Genome Recombination ◽

Simplex Virus ◽

Hsv 1

Wildtype adeno-associated virus (AAV) can only replicate in the presence of helper factors, which can be provided by co-infecting helper viruses such as adenoviruses and herpes viruses. The AAV genome consists of a linear, single-stranded DNA (ssDNA), which is converted into different molecular structures within the host cell. Using high throughput sequencing we found that herpes simplex virus type 1 (HSV-1) co-infection leads to a shift in the type of AAV genome end recombination. In particular, open-end ITR recombination was enhanced whereas open-closed ITR recombination was reduced in the presence of HSV-1. We demonstrate that the HSV-1 protein ICP8 plays an essential role in HSV-1 mediated interference with AAV genome end recombination, indicating that the previously described ICP8-driven mechanism of HSV-1 genome recombination may be underlying the observed changes. We also provide evidence that additional factors, such as products of true late genes, are involved. Although HSV-1 co-infection significantly changed the type of AAV genome end recombination, no significant change in the amount of circular AAV genomes was identified. IMPORTANCE AAV-mediated gene therapy represents one of the most promising approaches for the treatment of genetic diseases. Currently, various GMP-compatible production methods can be applied to manufacture clinical grade vector, including methods that employ helper factors derived form HSV-1. Yet to date we do not fully understand how HSV-1 interacts with AAV. We observed that HSV-1 modulates AAV genome ends similarly to the genome recombination events observed during HSV-1 replication and postulate that further improvements of the HSV-1 production platform may enhance packaging of the recombinant AAV particles.

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Cleavage in and around the DR1 Element of the aSequence of Herpes Simplex Virus Type 1 Relevant to the Excision of DNA Fragments with Length Corresponding to One and Two Units of the a Sequence

Journal of Virology ◽

10.1128/jvi.75.13.5870-5878.2001 ◽

2001 ◽

Vol 75 (13) ◽

pp. 5870-5878 ◽

Cited By ~ 6

Author(s):

Kenichi Umene

Keyword(s):

Herpes Simplex Virus ◽

Herpes Simplex ◽

Virus Type ◽

Herpes Simplex Virus Type ◽

Cleavage Site ◽

Dna Fragments ◽

Site Specific ◽

Simplex Virus ◽

Hsv 1

ABSTRACT The a sequence of herpes simplex virus type 1 (HSV-1) is a region bracketed by two direct repeats named DR1. Concatemeric HSV-1 DNA, the product of DNA replication, is cleaved at a specific site on the second DR1 distal from the S component (authentic cleavage) to yield unit-length linear HSV-1 DNA prior to or during packaging of HSV-1 DNA. The presence of two DNA bands, of 0.25 kb (shorter band) and 0.5 kb (longer band), the lengths of which correspond to one and two units of the a sequence, was identified using acrylamide gel electrophoresis of HSV-1 DNA preparations extracted by the method of Hirt. Twelve DNA fragments from each band were molecularly cloned, and nucleotide sequences were determined. Both termini of eight (67%) DNA clones from the shorter band corresponded to the specific cleavage site on DR1. Five (41%) DNA clones from the longer band had a terminus corresponding to the specific cleavage site on DR1 on one side, but not on the opposite side. Thirteen (54%) of 24 termini of 12 analyzed DNA clones from the longer band were in and around DR1. Thus, cleavage events of DR1 can be classified into three categories: (i) authentic cleavage; (ii) site-specific cleavage on the third DR1 distal from the S component (secondary site-specific cleavage), which is related to the generation of the shorter DNA band in combination with authentic cleavage; and (iii) less-specific cleavage events in and around other DR1 elements which relate to the generation of the longer DNA band.

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