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Epstein-Barr virus binding to CD21 activates the initial viral promoter via NF-kappaB induction.

Sugano N, Chen W, Roberts ML, Cooper NR - J. Exp. Med. (1997)

Bottom Line: Epstein-Barr virus (EBV), an oncogenic human herpesvirus, binds to and infects normal human B lymphocytes via CD21, the CR2 complement receptor.Studies of the mechanisms that enable EBV to infect nonactivated, noncycling B cells provide compelling evidence for a sequence of events in which EBV binding to CD21 on purified resting human B cells rapidly activates the NF-kappaB transcription factor, which, in turn, binds to and mediates transcriptional activation of Wp, the initial viral latent gene promoter.Thus, EBV binding to its cellular receptor on resting B cells triggers an NF-kappaB-dependent intracellular signaling pathway which is required for infection.

View Article: PubMed Central - PubMed

Affiliation: Scripps Research Institute, Department of Immunology, La Jolla, California 92037, USA.

ABSTRACT
Epstein-Barr virus (EBV), an oncogenic human herpesvirus, binds to and infects normal human B lymphocytes via CD21, the CR2 complement receptor. Studies of the mechanisms that enable EBV to infect nonactivated, noncycling B cells provide compelling evidence for a sequence of events in which EBV binding to CD21 on purified resting human B cells rapidly activates the NF-kappaB transcription factor, which, in turn, binds to and mediates transcriptional activation of Wp, the initial viral latent gene promoter. Thus, EBV binding to its cellular receptor on resting B cells triggers an NF-kappaB-dependent intracellular signaling pathway which is required for infection.

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NF-κB activated by EBV binding binds to and activates Wp. (A) Binding of activated NF-κB to the NF-κB–like site in Wp. Nuclear extracts from purified resting B cells 30 min after addition of EBV were evaluated for ability to bind to labeled probes duplicating the NF-κB–like site in  Wp (left), or an NF-κB consensus sequence (right), by EMSA. Competition studies were carried out with unlabeled probes reflecting the wild-type Wp sequence (Wp wt), Wp bearing a mutant NF-κB–like sequence (Wp mut), or the wild-type NF-κB consensus sequence (NF-κB). (B) Transcriptional activation of Wp by NF-κB. CAT activity assays were carried out in human 293 cells cotransfected with p50, p65, or p50 plus p65 expression plasmids together with a Wp CAT reporter plasmid, a Wp CAT reporter plasmid with a mutated NF-κB site, or an HIV CAT reporter plasmid.
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Figure 4: NF-κB activated by EBV binding binds to and activates Wp. (A) Binding of activated NF-κB to the NF-κB–like site in Wp. Nuclear extracts from purified resting B cells 30 min after addition of EBV were evaluated for ability to bind to labeled probes duplicating the NF-κB–like site in Wp (left), or an NF-κB consensus sequence (right), by EMSA. Competition studies were carried out with unlabeled probes reflecting the wild-type Wp sequence (Wp wt), Wp bearing a mutant NF-κB–like sequence (Wp mut), or the wild-type NF-κB consensus sequence (NF-κB). (B) Transcriptional activation of Wp by NF-κB. CAT activity assays were carried out in human 293 cells cotransfected with p50, p65, or p50 plus p65 expression plasmids together with a Wp CAT reporter plasmid, a Wp CAT reporter plasmid with a mutated NF-κB site, or an HIV CAT reporter plasmid.

Mentions: In examining the region in Wp 5′ to the TATA box, an NF-κB–like sequence was found (GGGGGACCAC versus GGGA/GNNC/TC/TCC for the NF-κB consensus binding sequence) beginning 19 nucleotides 5′ to the TATA box. Adenine, rather than cytosine, at position 9 has been reported to be occasionally used in NF-κB–binding sequences in other promoters (30). EMSAs revealed that nuclear extracts from resting B cells 30 min after EBV addition bound to an oligonucleotide that duplicated the Wp NF-κB–like sequence (Fig. 4 A). Binding was inhibited by an oligonucleotide with the same sequence and by a probe duplicating the NF-κB consensus binding site, but unaffected by a mutant Wp oligonucleotide (Fig. 4 A). Reciprocally, binding of the consensus NF-κB probe was competed by the Wp probe and the NF-κB consensus probe, but not by the mutant Wp probe (Fig. 4 A).


Epstein-Barr virus binding to CD21 activates the initial viral promoter via NF-kappaB induction.

Sugano N, Chen W, Roberts ML, Cooper NR - J. Exp. Med. (1997)

NF-κB activated by EBV binding binds to and activates Wp. (A) Binding of activated NF-κB to the NF-κB–like site in Wp. Nuclear extracts from purified resting B cells 30 min after addition of EBV were evaluated for ability to bind to labeled probes duplicating the NF-κB–like site in  Wp (left), or an NF-κB consensus sequence (right), by EMSA. Competition studies were carried out with unlabeled probes reflecting the wild-type Wp sequence (Wp wt), Wp bearing a mutant NF-κB–like sequence (Wp mut), or the wild-type NF-κB consensus sequence (NF-κB). (B) Transcriptional activation of Wp by NF-κB. CAT activity assays were carried out in human 293 cells cotransfected with p50, p65, or p50 plus p65 expression plasmids together with a Wp CAT reporter plasmid, a Wp CAT reporter plasmid with a mutated NF-κB site, or an HIV CAT reporter plasmid.
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Figure 4: NF-κB activated by EBV binding binds to and activates Wp. (A) Binding of activated NF-κB to the NF-κB–like site in Wp. Nuclear extracts from purified resting B cells 30 min after addition of EBV were evaluated for ability to bind to labeled probes duplicating the NF-κB–like site in Wp (left), or an NF-κB consensus sequence (right), by EMSA. Competition studies were carried out with unlabeled probes reflecting the wild-type Wp sequence (Wp wt), Wp bearing a mutant NF-κB–like sequence (Wp mut), or the wild-type NF-κB consensus sequence (NF-κB). (B) Transcriptional activation of Wp by NF-κB. CAT activity assays were carried out in human 293 cells cotransfected with p50, p65, or p50 plus p65 expression plasmids together with a Wp CAT reporter plasmid, a Wp CAT reporter plasmid with a mutated NF-κB site, or an HIV CAT reporter plasmid.
Mentions: In examining the region in Wp 5′ to the TATA box, an NF-κB–like sequence was found (GGGGGACCAC versus GGGA/GNNC/TC/TCC for the NF-κB consensus binding sequence) beginning 19 nucleotides 5′ to the TATA box. Adenine, rather than cytosine, at position 9 has been reported to be occasionally used in NF-κB–binding sequences in other promoters (30). EMSAs revealed that nuclear extracts from resting B cells 30 min after EBV addition bound to an oligonucleotide that duplicated the Wp NF-κB–like sequence (Fig. 4 A). Binding was inhibited by an oligonucleotide with the same sequence and by a probe duplicating the NF-κB consensus binding site, but unaffected by a mutant Wp oligonucleotide (Fig. 4 A). Reciprocally, binding of the consensus NF-κB probe was competed by the Wp probe and the NF-κB consensus probe, but not by the mutant Wp probe (Fig. 4 A).

Bottom Line: Epstein-Barr virus (EBV), an oncogenic human herpesvirus, binds to and infects normal human B lymphocytes via CD21, the CR2 complement receptor.Studies of the mechanisms that enable EBV to infect nonactivated, noncycling B cells provide compelling evidence for a sequence of events in which EBV binding to CD21 on purified resting human B cells rapidly activates the NF-kappaB transcription factor, which, in turn, binds to and mediates transcriptional activation of Wp, the initial viral latent gene promoter.Thus, EBV binding to its cellular receptor on resting B cells triggers an NF-kappaB-dependent intracellular signaling pathway which is required for infection.

View Article: PubMed Central - PubMed

Affiliation: Scripps Research Institute, Department of Immunology, La Jolla, California 92037, USA.

ABSTRACT
Epstein-Barr virus (EBV), an oncogenic human herpesvirus, binds to and infects normal human B lymphocytes via CD21, the CR2 complement receptor. Studies of the mechanisms that enable EBV to infect nonactivated, noncycling B cells provide compelling evidence for a sequence of events in which EBV binding to CD21 on purified resting human B cells rapidly activates the NF-kappaB transcription factor, which, in turn, binds to and mediates transcriptional activation of Wp, the initial viral latent gene promoter. Thus, EBV binding to its cellular receptor on resting B cells triggers an NF-kappaB-dependent intracellular signaling pathway which is required for infection.

Show MeSH
Related in: MedlinePlus