The BI'LF4 trans-activator of epstein-barr virus is modulated by type and differentiation of the host cell

Marschall, Manfred; Schwarzmann, Fritz; Leser, Ulrike; Oker, Barbara; Alliger, Peter; Mairhofer, Helga; Wolf, Hans

doi:10.1016/0042-6822(91)90482-q

Cited by 12 publications

(11 citation statements)

References 36 publications

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“…The quantitative differences between these two viral proteins indicate the experimental discrimination between a direct, low-level trans-activator of ori Lyt (BRLF 1) and the full lyric transition by a latency breaking gene (BZLF t). Furthermore, expression of BI'LF 4, described as an additional, specialized regulator of EBV genes [23] did not lead to a measurable lytic effect in this cell system.…”

Section: Resultsmentioning

confidence: 99%

“…The specific DNA sequences were introduced into the polylinker of p 220.2, using restriction sites Barn HI/Hin d III (pEBV 57) and Barn HI/Sal I (pEBV 59), respectively. Subcloning of the original viral sequences was described elsewhere: HBsAg coding sequence [22], BZLF 1 Lytic transition of Epstein-Barr virus imitated by recombinant B-cells 25 coding sequence [23] and CMV immediate early promoter-enhancer [4]. The ori Lyt regulatory element was subcloned as a 1060 bp fragment from the EBV Barn HI H clone [1,30] using Hin cII and Apa LI restriction sites.…”

Section: Construction Of Eukaryotic Vectorsmentioning

confidence: 99%

“…The slides were analyzed under the microscope at a magnification of 250. For Western blots, the applied standard immunotechniques and staining procedures were described previously [23].…”

Section: Immunofhtorescence and Western Blotmentioning

confidence: 99%

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The lytic transition of Epstein-Barr virus is imitated by recombinant B-cells

Marschall

Alliger

Schwarzmann

et al. 1993

Archives of Virology

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Summary. Lytic transition of Epstein-Barr virus (EBV) is initiated by distinctimmediate early regulators of the viral cycle, in synchronization to temporary, permissive conditions during host cell differentiation. We developed eukaryotic vectors suitable to imitate the processes involved in lyric transition in cell culture systems. Two stable B cell lines were established: R59Z activator cells were used to induce lytic EBV expression in a constitutive manner by the production of the BZLF 1 trans-activator (Zta). R7-57 reporter cells, on the other hand, signaled induced activity of the lyric origin of EBV replication (ori Lyt). Different modes, like chemical induction, lyric superinfection with EBV and single gene trans-activation converted the recombinant ori Lyt element in R7-57 reporter cells. BZLF 1, transiently expressed in R7-57 reporter cells, was the only EBV trans-activator found, sufficient in inducing the viral lytic cycle. Basing on these experiments, trans-cellular activation of EBV was tested by cocultivation of BZLF 1-expressing R59Z activator cells with the R7-57 reporter line. No lyric effect on the reporter cells could be measured, neither by cocultivation of activator cells nor by coincubation of BZLF 1-containing cell lysates. Latency breaking activity, however, was transferred from activator to reporter cells when active, exogenous virus was added. The cell system described in these experiments provides a tool for the detection of EBV reactivation and demonstrates the potential of the lytic regulatory gene BZLF 1.

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Section: Resultsmentioning

confidence: 99%

Section: Construction Of Eukaryotic Vectorsmentioning

confidence: 99%

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The lytic transition of Epstein-Barr virus is imitated by recombinant B-cells

Marschall

Alliger

Schwarzmann

et al. 1993

Archives of Virology

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“…However, in vivo latent infection of BDV was suggested in healthy human subjects with low antigen expression in addition to frequent reactivation in chronically ill patients (5). Latent infection for DNA viruses such as Epstein-Barr virus is associated with a downregulation of gene expression (6,27). On the other hand, persistent infection is the most common mechanism thus far adapted by RNA viruses for their maintenance within infected cells over periods that can extend for the life of the host.…”

Section: Discussionmentioning

confidence: 99%

Varied Persistent Life Cycles of Borna Disease Virus in a Human Oligodendroglioma Cell Line

Ibrahim

Watanabe

Palacios

et al. 2002

J Virol

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Borna disease virus (BDV) establishes a persistent infection inBorna disease virus (BDV) causes progressive meningoencephalomyelitis in horses and sheep, in addition to several other vertebrate species (4,26,41). BDV is a single nonsegmented, negative-stranded (NNS) RNA virus (7,11,14,42) that is unique among members of the order Mononegaverales, in that it uses the nucleus as a site for replication and transcription (10, 43). BDV is a highly neurotropic virus that persists in the central nervous system (CNS) of infected animals. In adult rats, BDV infection is associated with massive brain inflammation and extensive neuronal damage (33). Neonatal infection, by contrast, results in life-long persistence without encephalitis (2,3,8,16,33). However, infected rats of all ages express a variety of behavioral abnormalities. Therefore, BDV provides an important model for the investigation of the mechanisms and consequences of viral persistence in the CNS.Generally, the CNS is known to be unique in its response to viral infections. This may be because of the lack of specialized lymphatic drainage, potentially limiting and delaying viral antigen recognition, in addition to the lack of dendritic cells and the use of microglia for the initial recognition and presentation of viral antigens, as well as the lack of expression of major histocompatibility molecules by normal neurons and glial cells (36). Thus, these factors result in immune limitations, which could contribute to the fate of viral persistence in the CNS, in general and for BDV as well. In addition, persistent BDV infection in the CNS is due to its noncytolytic strategy for replication (25).Persistent infection with BDV has been established in a variety of neuronal and glial cell lines during which viral antigens are continuously detected (9). The choice of a cell line for the in vitro characterization of BDV appears to depend on the in vivo tropism of the virus, as well as on the functional importance and abundance of cells in the CNS such as neurons and glial cells (astrocytes and oligodendrocytes). The rat astrocytoma cell line (C6) is frequently used for such a purpose (9, 17), in addition to the neuronal cell lines SK-N-SH and SK-N-SHEP (9).The cell-specific variations in BDV replication in vitro have been studied. BDV persistence in the C6 cell line is characterized by high-level expression of BDV-specific proteins and RNA and low-level production of infectious virions (9). Such an expression is related in part to the secretion of several neurotrophic factors into the culture medium by the cells (9, 35). Although BDV is characterized by high genomic stability, a recent report demonstrated the possibility of isolating stable virus variants from a persistently infected C6 cell line (17).Although oligodendrocytes are a major cellular component of the white matter in the CNS and have a pivotal role in neuronal cell functions, they have not been well studied in terms of BDV characterization. Oligodendrocytes have been shown to support experimental and natural i...

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“…Sequence analysis of the surface glycoprotein HEF of C/AA-pi virus revealed a distinct variation in the putative receptor binding domain, associated with the capacity to infect cells carrying low receptor levels . (iv) Cell-type specificity for persistent infection, as outlined by our results, has been investigated intensively for latent DNA viruses, for instance Epstein-Barr virus (Bogedain et al, 1994;Marschall et aL, 1991;Schwarzmann et al, 1994). In this case latency is characterized by complex down-regulation of gene expression, as accomplished by virus--cell interregulation in privileged tissues.…”

Section: Cell-type Specific Support Of Persistencementioning

confidence: 99%