The genome of herpesvirus saimiri C488 which is capable of transforming human T cells

Ensser, Armin; Thurau, Mathias; Wittmann, Sabine; Fickenscher, Helmut

doi:10.1016/s0042-6822(03)00449-5

Cited by 52 publications

(69 citation statements)

References 119 publications

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“…Therefore, we evaluated the expression of the latency-associated orf73 gene or a lytically expressed gene that encodes the viral envelope protein, glycoprotein B (orf8). 21 RT-PCR was performed on cDNA samples derived from HVS-transduced cells or their mocktransduced counterparts grown in a CFU-GEMM assay or using the liquid erythroid differentiation conditions. The results shown in Figure 3b demonstrate expression of the orf73 gene in HVS-transduced cultures.…”

Section: Hvs Transduction Of Human Haemopoietic Progenitorsmentioning

confidence: 99%

Marker gene transfer into human haemopoietic cells using a herpesvirus saimiri-based vector

et al. 2004

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Herpesvirus-based gene therapy vectors offer an attractive alternative to retroviral vectors because of their episomal nature and ability to accommodate large transgenes. Saimiriine herpesvirus 2 (HVS) is a prototypical gamma-2 herpesvirus that can latently infect numerous different cell types. A cosmid-generated HVS vector in which transforming genes have been deleted and the marker gene encoding enhanced green fluorescent protein (HVS-GFP) has been incorporated was evaluated for its potential to transduce CD34+ haemopoietic progenitors selected from cord blood.Expression of GFP could subsequently be readily detected in cells of the erythroid lineage in both CFU-GEMM assays and liquid differentiation cultures. These results confirm the potential of HVS as a candidate vector for gene therapy applications using primitive haemopoietic cells and suggest that it may be applicable to disorders affecting cells of the erythroid lineage.

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Section: Hvs Transduction Of Human Haemopoietic Progenitorsmentioning

confidence: 99%

Marker gene transfer into human haemopoietic cells using a herpesvirus saimiri-based vector

et al. 2004

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“…The ORF5 genes of HVS strains A11 and strain C488 were originally predicted to encode 81 and 72 amino acids, respectively (1,18). However, the extensive sequence variation at the amino terminus suggested potential splicing of the ORF5-coding sequence.…”

Section: Resultsmentioning

confidence: 99%

“…Previous sequence analysis indicated the presence of a small open reading frame, encoding ORF5, in the HVS subgroup A and C genomes (1,18). Despite strong conservation of the ORF5 gene between two strains, the ORF5 proteins of subgroup A strain 11 and subgroup C strain 488 showed dramatic sequence variation throughout the coding sequence, particularly in the amino-terminal region.…”

Section: Discussionmentioning

confidence: 99%

Modulation of T-Cell Receptor Signal Transduction by Herpesvirus Signaling Adaptor Protein

Lee

Chung

Cho

et al. 2004

Molecular and Cellular Biology

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Because of its central regulatory role, T-cell receptor (TCR) signal transduction is a common target of viruses. We report here the identification of a small signaling protein, ORF5, of the T-lymphotropic tumor virus herpesvirus saimiri (HVS). ORF5 is predicted to contain 89 to 91 amino acids with an amino-terminal myristoylation site and six SH2 binding motifs, showing structural similarity to cellular LAT (linker for activation of T cells). Sequence analysis showed that, despite extensive sequence variation, the myristoylation site and SH2 binding motifs were completely conserved among 13 different ORF5 isolates. Upon TCR stimulation, ORF5 was efficiently tyrosine phosphorylated and subsequently interacted with cellular SH2-containing signaling proteins Lck, Fyn, SLP-76, and p85 through its tyrosine residues. ORF5 expression resulted in the marked augmentation of TCR signal transduction activity, evidenced by increased cellular tyrosine phosphorylation, intracellular calcium mobilization, CD69 surface expression, interleukin-2 production, and activation of the NF-AT, NF-B, and AP-1 transcription factors. Despite its structural similarity to cellular LAT, however, ORF5 could only partially substitute for LAT function in TCR signal transduction. These results demonstrate that HVS utilizes a novel signaling protein, ORF5, to activate TCR signal transduction. This activation probably facilitates viral gene expression and, thereby, persistent infection.Upon engagement of the T-cell antigen receptor (TCR), many cellular proteins, including TCR subunits, adaptor proteins, and other effector molecules, are phosphorylated and subsequently are involved in the formation of molecular complexes at the site of contact with the antigen-presenting cells (33, 51, 54) The earliest signaling event following TCR engagement is the sequential activation of the non-receptor protein tyrosine kinases (PTKs) of the Src and Syk families. Activated Src family PTKs, Lck and Fyn, in T cells subsequently phosphorylate tyrosine residues within a consensus sequence termed the immunoreceptor tyrosine-based activation motif in the cytosolic tails of the TCR subunits. The phosphorylated immunoreceptor tyrosine-based activation motifs of TCR in turn recruit the Syk family PTKs ZAP70 and Syk through their Src homology 2 (SH2) domains (33). Together with Lck and Fyn, the ZAP70 and Syk kinases then promote the phosphorylation of many intracellular signaling molecules, including phospholipase C-␥1 (PLC-␥1), Cbl, Vav, LAT (linker for activation of T cells) and SLP-76 (SH2-containing leukocyte protein-76) (12,25,41,45,46,53). Phosphorylation of these cellular signaling molecules ultimately induces various cellular events such as cytoskeletal alteration, intracellular Ca ϩϩ influx, transcription factor activation, and cytokine/chemokine production (4,20,38,43,59).Two adaptor proteins, LAT and SLP-76, have been shown to be critical for the optimal activation of T cells and to function in linking proximal signaling events to distal downstream signaling ac...

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“…25,37 The markerless release of the enhanced green fluorescent protein (EGFP) cassette and the reconstitution of the original virus sequence was achieved by en passant mutagenesis. 38,39 For constructing RT-hTERT BAC488, the expression cassette for hTERT was inserted into orf75 by homologous recombination.…”

Section: Recombinant Hvs Vectors For Htert Expressionmentioning

confidence: 99%

“…37 The pBeloBAC11 vector (Invitrogen, Karlsruhe, Germany) was linearized with SalI to remove the cos and loxP sites. The remaining mini-F vector components were cloned into a unique KpnI restriction site of cos261 within the dispensable HVS C488 orf14.…”

Section: Vectors and Recombinant Virusesmentioning

confidence: 99%

Rhadinovirus vector-derived human telomerase reverse transcriptase expression in primary T cells

2010

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The rhadinovirus herpesvirus saimiri (HVS) as a gene delivery vector allows large DNA insertions and long-termed gene expression. In the case of T-cell transduction, such vectors use the viral transformation-associated genes of HVS C488 for T-cell amplification. In this report, we investigated whether the gene for the catalytic telomerase subunit human telomerase reverse transcriptase (hTERT) can substitute for the transformation-associated genes in rhadinoviral T-cell transduction and amplification. By using virus mutants generated by en passant mutagenesis from bacterial artificial chromosomes, we observed a very early and functional transgene expression even by virus mutants without transformation-associated genes. The markers of T-cell transformation by HVS, namely CD2 hyperreactivity, overexpression of interleukin-26, and of the tyrosine kinase Lyn could neither be induced nor enhanced by ectopic hTERT expression. When the viral transformation-associated genes were replaced by the hTERT gene, it was not sufficient for growth transformation, although hTERT was efficiently transduced and functionally expressed by the rhadinovirus vector. Thus, the transformation-associated proteins StpC and Tip are responsible for the T-cell phenotype after transduction by HVS and, additionally, modulate telomerase activity independently of hTERT expression.

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The genome of herpesvirus saimiri C488 which is capable of transforming human T cells

Cited by 52 publications

References 119 publications

Marker gene transfer into human haemopoietic cells using a herpesvirus saimiri-based vector

Marker gene transfer into human haemopoietic cells using a herpesvirus saimiri-based vector

Modulation of T-Cell Receptor Signal Transduction by Herpesvirus Signaling Adaptor Protein

Rhadinovirus vector-derived human telomerase reverse transcriptase expression in primary T cells

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