DNA sequence heterogeneity within the Epstein–Barr virus family of repeats in the latent origin of replication

Fruscalzo, Alberto; Marsili, Giulia; Busiello, V.; Bertolini, Luisa; Frezza, Domenico

doi:10.1016/s0378-1119(01)00345-6

Cited by 14 publications

(31 citation statements)

References 24 publications

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“…Annealed oligonucleotides (5-CATGGCC AGATATTTGGAGATCT-3 and 5-GTACAGATCTCCAAATATCTGGC-3), constituting a BstXI site, were then inserted into NcoI-BsrGI-digested pFR29-⌬NB to generate pFR29-BstXI. The BstXI fragment of the pFR29-BstXI plasmid contains the 252-bp region that is missing in the EBV B95-8 strain sequence (5). The reporter construct pFR9(hairpinϩ)-Luc was constructed by cloning the BstXI fragment of pFR29-BstXI into the BstXI site of p⌬FR20.…”

Section: Methodsmentioning

confidence: 99%

“…A recent study reported that the number of 30-bp repeat units within the EBV FR varies between strains; for example, the FR of the EBV B95-8 strain, a prototype EBV, consists of 29 copies of the 30-bp repeat unit (5). Unlike other repetitive sequences that alter their copy numbers during viral DNA replication, the size of the FR appears to be strictly conserved within each EBV strain.…”

mentioning

confidence: 99%

“…Unlike other repetitive sequences that alter their copy numbers during viral DNA replication, the size of the FR appears to be strictly conserved within each EBV strain. Each viral strain maintains its characteristic number of FRs during long-term passaging of the cells (5). Thus, the length of the FR can be used to categorize different EBV strains.…”

mentioning

confidence: 99%

“…Curiously, there is a discrepancy between the number of 30-bp units within the FR of the so-called oriP miniplasmid (such as pCEP4 [Invitrogen]) and that of the original EBV B95-8 strain from which it is derived (5). The FR of the commonly used oriP plasmid consists of only 20 copies of the 30-bp unit (21).…”

mentioning

confidence: 99%

“…A 252-bp DNA sequence, which corresponds to almost nine copies of the 30-bp repeats, is missing from the oriP miniplasmid, as well as from the GenBank sequence of the EBV B95-8 strain (V01555) (2). It is most likely that the 252-bp deletion in the FR occurred while subcloning EBV genomic DNA fragments into plasmid vectors (5). By contrast, the DS sequence is stably maintained before, and after, subcloning, demonstrating that the FR is subject to instability.…”

mentioning

confidence: 99%

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Distinctive Effects of the Epstein-Barr Virus Family of Repeats on Viral Latent Gene Promoter Activity and B-Lymphocyte Transformation

Ali

Saito

Shibata

et al. 2009

J Virol

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The Epstein-Barr virus (EBV), a human B-lymphotropic gamma herpesvirus, contains multiple repetitive sequences within its genome. A group of repetitive sequences, known as the family of repeats (FR), contains multiple binding sites for the viral trans-acting protein EBNA-1. The FR sequences are important for viral genome maintenance and for the regulation of the promoter involved in viral latent gene expression. It has been reported that a palindromic sequence with a putative secondary structure exists at the 3 end of the FR in the genome of the EBV B95-8 strain and that this palindromic sequence has been deleted from the FR of the commonly used EBV miniplasmids. For the first time, we cloned an EBV B95-8 DNA fragment containing the full-length FR, which enabled us to examine the functional difference between full-length and deleted FRs. The full-length FR, like the deleted FR, functioned as a transcriptional enhancer of the viral latent gene promoter, but that transactivation was significantly attenuated in the case of the full-length FR. No significant enhancement of replication was observed when the deleted FR was replaced with the full-length FR in an EBV miniplasmid. By contrast, when the same set of FR sequences were tested in the context of the complete EBV genome, the full-length FR resulted in more-efficient B-cell transformation than the deleted FR. We propose that the presence of the full-length FR contributes to the precise regulation of the viral latent promoter and increases the efficiency of B-cell transformation.

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Distinctive Effects of the Epstein-Barr Virus Family of Repeats on Viral Latent Gene Promoter Activity and B-Lymphocyte Transformation

Ali

Saito

Shibata

et al. 2009

J Virol

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Transmission in vitro of hepatitis C virus from persistently infected human B-cells to hepatoma cells by cell-to-cell contact

et al. 2005

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Virus cell-to-cell spread has been reported for many different viruses and may contribute to pathogenesis of viral disease. The role played by cell-to-cell contact in hepatitis C virus (HCV) transmission was studied in vitro by cell co-cultivation experiments. A human lymphoblastoid B-cell line, infected persistently with HCV in vitro (TO.FE(HCV)), was used as HCV donor [Serafino et al., 2003]; recipient cells were the human hepatoma HepG2 cell line. Both cell types were co-cultured for 48 hr to allow the cell-to-cell contacts. The hepatoma HepG2 cells are not permissive to free-virus infection, but they were infected successfully using TO.FE(HCV) cells as source of virus. The kinetics of viral RNA synthesis and the percentage of infected cells were compared in cell-mediated-and cell-free-viral infection. After co-cultivation, a consistent proportion of hepatoma cells replicated HCV and stably expressed viral antigens. Virus produced was infectious as demonstrated by the ability to reinfect fresh B-cells. This cell model shows that permissiveness to HCV infection can be achieved in vitro in non-permissive hepatoma cells by direct cell-to-cell contacts with infected human B-cells. This mechanism of virus spread may also play a pathogenic role in vivo.

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Molecular and cellular determinants of cell‐to‐cell transmission of HCV in vitro

Valli

Crema

Lanzilli

et al. 2007

Journal of Medical Virology

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It was reported previously that HCV can be transmitted from persistently infected human bone-marrow-derived B-lymphoblastoid cells (TO.FE(HCV)) to human hepatoma cells by cell-to-cell contact. The present study confirms and characterize further such type of HCV infection in vitro. TO.FE(HCV) cells were co-cultured with 2.2.15 hepatoma cells, that are not susceptible to cell-free infection by sera containing HCV of 1b genotype. By this co-cultivation system it was demonstrated that HCV transmission to recipient cells requires de novo virus RNA replication. Several factors may favor HCV-transmission, evidence is provided that TO.FE(HCV) cells were able to select HCV-quasispecies. 5'-UTR and core sequence analysis revealed differences in the HCV-quasispecies composition in serum inoculum and in infected TO.FE B-cells at 4 months post-inoculation. It is considered that the latter may be more successful in replicating HCV in vitro and used to express surface molecules which may be involved in cell-to-cell contact. In TO.FE(HCV) cells replicate distinct, or few close related, HCV-variants correlated with those of serum inoculum. Comparative analysis of tetra-spans and integrins expression undertaken by cytofluorimetry displayed higher level of expression for TO.FE cells in comparison to other human bone-marrow-derived B-cell lines. Overall, the observed persistent in vitro HCV replication is mediated by a continuous cell-to-cell reinfection that may be favored by selection of viral variants and expression of molecules involved in cell adhesion. These observations may provide an explanation for the establishment of HCV infection, the occurrence of chronic infection and HCV-related lymphoproliferative diseases.

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DNA sequence heterogeneity within the Epstein–Barr virus family of repeats in the latent origin of replication

Cited by 14 publications

References 24 publications

Distinctive Effects of the Epstein-Barr Virus Family of Repeats on Viral Latent Gene Promoter Activity and B-Lymphocyte Transformation

Distinctive Effects of the Epstein-Barr Virus Family of Repeats on Viral Latent Gene Promoter Activity and B-Lymphocyte Transformation

Transmission in vitro of hepatitis C virus from persistently infected human B-cells to hepatoma cells by cell-to-cell contact

Molecular and cellular determinants of cell‐to‐cell transmission of HCV in vitro

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