Production of an infectious Herpesvirus saimiri-based episomally maintained amplicon system

Macnab, Stuart A; White, Rob; Hiscox, Julian A.; Whitehouse, Adrian

doi:10.1016/j.jbiotec.2008.01.012

Cited by 11 publications

(13 citation statements)

References 44 publications

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“…Therefore, it offers the characteristics of an artificial chromosome combined with a highly efficient delivery system. Further developments include the generation of an HVS amplicon system to both improve biosafety and increase transgene capacity (51), thus enabling the generation of a single gene delivery vector encompassing all of the factors required for efficient reprogramming. In this paper, we show the potential of HVS-based vectors for the reprogramming of cancer cells; in the future, a further development would be to use their large packaging capability to produce a single vector expressing the appropriate reprogramming factors.…”

Section: Discussionmentioning

confidence: 99%

Potential of Herpesvirus Saimiri-Based Vectors To Reprogram a Somatic Ewing's Sarcoma Family Tumor Cell Line

Brown

Unger

Whitehouse

2013

J Virol

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cHerpesvirus saimiri (HVS) infects a range of human cell types with high efficiency. Upon infection, the viral genome can persist as high-copy-number, circular, nonintegrated episomes that segregate to progeny cells upon division. This allows HVS-based vectors to stably transduce a dividing cell population and provide sustained transgene expression in vitro and in vivo. Moreover, the HVS episome is able to persist and provide prolonged transgene expression during in vitro differentiation of mouse and human hemopoietic progenitor cells. Together, these properties are advantageous for induced pluripotent stem cell (iPSC) technology, whereby stem cell-like cells are generated from adult somatic cells by exogenous expression of specific reprogramming factors. Here we assess the potential of HVS-based vectors for the generation of induced pluripotent cancer stem-like cells (iPCs). We demonstrate that HVS-based exogenous delivery of Oct4, Nanog, and Lin28 can reprogram the Ewing's sarcoma family tumor cell line A673 to produce stem cell-like colonies that can grow under feeder-free stem cell culture conditions. Further analysis of the HVS-derived putative iPCs showed some degree of reprogramming into a stem cell-like state. Specifically, the putative iPCs had a number of embryonic stem cell characteristics, staining positive for alkaline phosphatase and SSEA4, in addition to expressing elevated levels of pluripotent marker genes involved in proliferation and self-renewal. However, differentiation trials suggest that although the HVS-derived putative iPCs are capable of differentiation toward the ectodermal lineage, they do not exhibit pluripotency. Therefore, they are hereby termed induced multipotent cancer cells.

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Section: Discussionmentioning

confidence: 99%

Potential of Herpesvirus Saimiri-Based Vectors To Reprogram a Somatic Ewing's Sarcoma Family Tumor Cell Line

Brown

Unger

Whitehouse

2013

J Virol

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“…These include Herpes simplex virus-1, Pseudorabies, Epstein-Barr virus and human cytomegalovirus. 2,10 Recent advances in this field include the development of a recombinant g-2 herpesvirus saimiri (HVS) amplicon system, which has the potential to deliver upwards of 50-150 kb heterologous DNA. 10 HVS has potential to be used in a range of protocols, as it can infect a wide variety of cells including colorectal, breast, lung, liver, kidney and a variety of white blood cells, whilst being episomally maintained in a dividing cell population in both in vitro and in vivo studies.…”

Section: Human Artificial Chromosomes S Macnab and A Whitehousementioning

confidence: 99%

“…2,10 Recent advances in this field include the development of a recombinant g-2 herpesvirus saimiri (HVS) amplicon system, which has the potential to deliver upwards of 50-150 kb heterologous DNA. 10 HVS has potential to be used in a range of protocols, as it can infect a wide variety of cells including colorectal, breast, lung, liver, kidney and a variety of white blood cells, whilst being episomally maintained in a dividing cell population in both in vitro and in vivo studies. 11,12 Important in vivo studies regarding the ability of HVS to deliver and express transgenes include the expression of bovine growth hormone in New World primates, as well as nude mouse tumour xenograft studies and intraperitoneal and intravenous HVS injection in mice.…”

Section: Human Artificial Chromosomes S Macnab and A Whitehousementioning

confidence: 99%

Progress and prospects: human artificial chromosomes

Macnab

Whitehouse

2009

Gene Ther

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“…Moreover, the minimal C terminus region, comprising residues 285-407, is sufficient to maintain the HVS episome in a dividing cell population. This analysis will help towards the development of safe replication-disabled HVS-based vectors for gene therapy applications, such as the HVS amplicon system (Macnab et al, 2008). The region identified herein, required for HVS episomal maintenance, will help minimize the viral sequence required in these HVS amplicon-based vectors.…”

mentioning

confidence: 94%

Mapping the minimal regions within the ORF73 protein required for herpesvirus saimiri episomal persistence

Griffiths

Harrison

Macnab

et al. 2008

Journal of General Virology

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Herpesvirus saimiri (HVS) establishes a persistent infection in which the viral genome persists as a circular non-integrated episome. ORF73 tethers HVS episomes to host mitotic chromosomes, allowing episomal persistence via an interaction with the chromosome-associated protein, MeCP2. Here we demonstrate that ORF73 also interacts with the linker histone H1 via its C terminus, suggesting it associates with multiple chromosome-associated proteins. In addition, we show that the C terminus is also required for the ability of ORF73 to bind the terminal repeat region of the HVS genome. These results suggest that the ORF73 C terminus contains all the necessary elements required for HVS episomal persistence. Using a range of ORF73 C terminus deletions to rescue the episomal maintenance properties of a HVSD73 recombinant virus, we show that a C terminus region comprising residues 285-407 is sufficient to maintain the HVS episome in a dividing cell population.Herpesvirus saimiri (HVS) is the prototype gamma-2 herpesviruses which causes an asymptomatic, but persistent, infection in squirrel monkeys (Fickenscher & Fleckenstein, 2001). In a manner comparable to other gamma herpesviruses, HVS establishes a latent persistent infection in lymphoid and epithelial cell populations, where the viral genome persists as a high copy number circular non-integrated episome (Kaschka-Dierich et al., 1982;Werner et al., 1977). This ability to persist as an nonintegrated episome has led to the development of HVS as a possible gene delivery vector (Calderwood et al., 2004b;Griffiths et al., 2006). To sustain this persistent infection in a dividing cell population, the viral episomes must be replicated during mitosis and segregated efficiently into daughter cells (Biesinger et al., 1992). The HVS ORF73 protein has been implicated in the maintenance of the viral episome during cell division (Hall et al., 2000a). HVS ORF73 colocalizes with HVS genomic DNA on host mitotic chromosomes (Calderwood et al., 2004a;Verma & Robertson, 2003), and it maintains the stability of HVS terminal repeat (TR)-containing plasmids Verma & Robertson, 2003). Moreover, deletion analysis of the HVS-BAC demonstrated that both ORF73 and the TR regions of HVS are required for episomal maintenance (Calderwood et al., 2005;White et al., 2003). These results suggest that the HVS ORF73 is a functional homologue of Kaposi's sarcoma associated herpesvirus (KSHV) latency-associated nuclear antigen (LANA; Ballestas et al., 1999;Ballestas & Kaye, 2001), and tethers the HVS episomes to host mitotic chromosomes, via the TR region of the HVS genome.Studies of KSHV LANA have shown that chromosome binding is achieved through interactions with multiple cellular chromosome-associated proteins, including MeCP2, DEK, core histones H2A and H2B, the linker histone H1 and cellular bromodomain-containing proteins (Barbera et al., 2006;Cotter & Robertson, 1999;Krithivas et al., 2002; Shinohara et al., 2002; Viejo-Borbolla et al., 2005). We have recently demonstrated that HVS ORF73 associates ...

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Production of an infectious Herpesvirus saimiri-based episomally maintained amplicon system

Cited by 11 publications

References 44 publications

Potential of Herpesvirus Saimiri-Based Vectors To Reprogram a Somatic Ewing's Sarcoma Family Tumor Cell Line

Potential of Herpesvirus Saimiri-Based Vectors To Reprogram a Somatic Ewing's Sarcoma Family Tumor Cell Line

Progress and prospects: human artificial chromosomes

Mapping the minimal regions within the ORF73 protein required for herpesvirus saimiri episomal persistence

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