Dataset Information

Inhibition of p53-dependent, but not p53-independent, cell death by U19 protein from human herpesvirus 6B.

ABSTRACT: Infection with human herpesvirus (HHV)-6B alters cell cycle progression and stabilizes tumor suppressor protein p53. In this study, we have analyzed the activity of p53 after stimulation with p53-dependent and -independent DNA damaging agents during HHV-6B infection. Microarray analysis, Western blotting and confocal microscopy demonstrated that HHV-6B-infected cells were resistant to p53-dependent arrest and cell death after ? irradiation in both permissive and non-permissive cell lines. In contrast, HHV-6B-infected cells died normally through p53-independet DNA damage induced by UV radiation. Moreover, we identified a viral protein involved in inhibition of p53 during HHV-6B-infection. The protein product from the U19 ORF was able to inhibit p53-dependent signaling following ? irradiation in a manner similar to that observed during infection. Similar to HHV-6B infection, overexpression of U19 failed to rescue the cells from p53-independent death induced by UV radiation. Hence, infection with HHV-6B specifically blocks DNA damage-induced cell death associated with p53 without inhibiting the p53-independent cell death response. This block in p53 function can in part be ascribed to the activities of the viral U19 protein.

SUBMITTER: Kofod-Olsen E

PROVIDER: S-EPMC3608612 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Inhibition of p53-dependent, but not p53-independent, cell death by U19 protein from human herpesvirus 6B.

Kofod-Olsen Emil E Møller Janni M L JM Schleimann Mariane H MH Bundgaard Bettina B Bak Rasmus O RO Øster Bodil B Mikkelsen Jacob G JG Hupp Ted T Höllsberg Per P

PloS one 20130326 3

Infection with human herpesvirus (HHV)-6B alters cell cycle progression and stabilizes tumor suppressor protein p53. In this study, we have analyzed the activity of p53 after stimulation with p53-dependent and -independent DNA damaging agents during HHV-6B infection. Microarray analysis, Western blotting and confocal microscopy demonstrated that HHV-6B-infected cells were resistant to p53-dependent arrest and cell death after γ irradiation in both permissive and non-permissive cell lines. In con ...[more]

PMID: 23555634

Similar Datasets

Project description:The "omics" revolution of recent years has simplified the study of RNA transcripts produced during viral infection and under specific defined conditions. In the quest to find new and differentially expressed transcripts during the course of human Herpesvirus 6B (HHV-6B) infection, we made use of large-scale RNA sequencing to analyze the HHV-6B transcriptome during productive infection of human Molt-3 T-cells. Analyses were performed at different time points following infection and specific inhibitors were used to classify the kinetic class of each open reading frame (ORF) reported in the annotated genome of HHV-6B Z29 strain. The initial search focussed on HHV-6B-specific reads matching new HHV-6B transcripts. Differential expression of new HHV-6B transcripts were observed in all samples analyzed. The presence of many of these new HHV-6B transcripts were confirmed by RT-PCR and Sanger sequencing. Many of these transcripts represented new splice variants of previously reported ORFs, including some transcripts that have yet to be defined. Overall, our work demonstrates the diversity and the complexity of the HHV-6B transcriptome.IMPORTANCERNA sequencing (RNA-seq) is an important tool for studying RNA transcripts, particularly during active viral infection. We made use of RNA-seq to study human Herpesvirus 6B (HHV-6B) infection. Using six different time points, we were able to identify the presence of differentially spliced genes at 6, 9, 12, 24, 48 and 72 hours post-infection. Determination of the RNA profiles in the presence of cycloheximide (CHX) or phosphonoacetic acid (PAA) also permitted identification of the kinetic class of each ORF described in the annotated GenBank file. We also identified new spliced transcripts for certain genes and evaluated their relative expression over time. These data and next-generation sequencing (NGS) of the viral DNA have led us to propose a new version of the HHV-6B Z29 GenBank annotated file, without changing ORF names in order to facilitate trace back and correlate our work with previous studies on HHV-6B.

Project description:Tetraspanins are four-span transmembrane proteins that organize the membrane by forming tetraspanin-enriched microdomains. These have been shown to be important for virus entry. The human herpesvirus (HHV)-6A receptor CD46 is known to form complexes with the tetraspanin CD9 and β1-integrins, however the significance of this for HHV-6A infection remains unexplored. Using a genetic approach, we demonstrate that knock out of CD46 abolishes binding to and infection of SupT1 cells by both HHV-6A and HHV-6B, establishing CD46 as a necessary receptor for productive infection of these cells. Knock out of CD9 in SupT1 cells had no effect on binding of either virus to the cell surface, but it reduced expression of immediate early transcripts to between 25-60% compared with the wild type cells. Although HHV-6B required CD46 for infection of SupT1, infection of Molt3 cells was independent of CD46 expression. Conversely, the absence of CD9 expression promoted infection of Molt3 cells with HHV-6B, indicating a negative role of CD9 for CD46-independent infection. Taken together, these data demonstrate that CD9 modulates infection with HHV-6A/B by promoting CD46-dependent infection and impairing CD46-independent infection. This also suggests that HHV-6A is strictly dependent on CD46 for entry, although other proteins, like CD9, may enhance the infection, whereas HHV-6B is more promiscuous and may use CD134, as demonstrated by others, CD46 in SupT1, and a novel yet unidentified receptor in Molt3 cells.Importance The mechanisms of entry of human herpesvirus (HHV)-6A and HHV-6B into host cells are of significance in order to develop novel drugs that may inhibit infection. To elucidate the contribution of the membrane proteins CD9 and CD46, we employed a genetic approach that eliminated these molecules from the host cell. This demonstrated that CD46 is critical for infection by HHV-6A, whereas infection by HHV-6B appeared to be more promiscuous. The infection of a T-cell line in the absence of CD46 and CD134 strongly suggest that an additional receptor for HHV-6B entry exists. Moreover, elimination of CD9 and subsequent reconstitution experiments demonstrated that CD9 promoted infection with HHV-6A and HHV-6B mediated by CD46, but inhibited infection with HHV-6B that occurred independent of CD46. Together, this demonstrated a CD46-dependent role of CD9 during infection with HHV-6A and HHV-6B and emphasized that HHV-6B may employ different entry mechanisms in various cells.

Project description:BACKGROUND: Human herpesvirus-6 (HHV-6) is a beta-herpesvirus with 90% seroprevalence that infects and establishes latency in the central nervous system. Two HHV-6 variants are known: HHV-6A and HHV-6B. Active infection or reactivation of HHV-6 in the brain is associated with neurological disorders, including epilepsy, encephalitis, and multiple sclerosis. In a preliminary study, we found HHV-6B DNA in resected brain tissue from patients with mesial temporal lobe epilepsy (MTLE) and have localized viral antigen to glial fibrillary acidic protein (GFAP)-positive glia in the same brain sections. We sought, first, to determine the extent of HHV-6 infection in brain material resected from MTLE and non-MTLE patients; and second, to establish in vitro primary astrocyte cultures from freshly resected brain material and determine expression of glutamate transporters. METHODS AND FINDINGS: HHV-6B infection in astrocytes and brain specimens was investigated in resected brain material from MTLE and non-MTLE patients using PCR and immunofluorescence. HHV-6B viral DNA was detected by TaqMan PCR in brain resections from 11 of 16 (69%) additional patients with MTLE and from zero of seven (0%) additional patients without MTLE. All brain regions that tested positive by HHV-6B variant-specific TaqMan PCR were positive for viral DNA by nested PCR. Primary astrocytes were isolated and cultured from seven epilepsy brain resections and astrocyte purity was defined by GFAP reactivity. HHV-6 gp116/54/64 antigen was detected in primary cultured GFAP-positive astrocytes from resected tissue that was HHV-6 DNA positive-the first demonstration of an ex vivo HHV-6-infected astrocyte culture isolated from HHV-6-positive brain material. Previous work has shown that MTLE is related to glutamate transporter dysfunction. We infected astrocyte cultures in vitro with HHV-6 and found a marked decrease in glutamate transporter EAAT-2 expression. CONCLUSIONS: Overall, we have now detected HHV-6B in 15 of 24 patients with mesial temporal sclerosis/MTLE, in contrast to zero of 14 with other syndromes. Our results suggest a potential etiology and pathogenic mechanism for MTLE.

Dataset Information

Inhibition of p53-dependent, but not p53-independent, cell death by U19 protein from human herpesvirus 6B.

Publications

Inhibition of p53-dependent, but not p53-independent, cell death by U19 protein from human herpesvirus 6B.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets