Neutrality of the canonical NF-kappaB-dependent pathway for human and murine cytomegalovirus transcription and replication in vitro.
Cytomegalovirus (CMV) is known to rapidly induce activation of nuclear factor kappaB (NF-kappaB) after infection of fibroblast and macrophage cells. NF-kappaB response elements are present in the enhancer region of the CMV major immediate-early promoter (MIEP), and activity of the MIEP is strongly upregulated by NF-kappaB in transient-transfection assays. Here we investigate whether the NF-kappaB-dependent pathway is required for initiating or potentiating human and murine CMV replication in vitro. We show that expression of a dominant negative mutant of the inhibitor of NF-kappaB-alpha (IkappaBalphaM) does not alter the replication kinetics of human or mouse CMV in cultured cells. In addition, mouse embryo fibroblasts genetically deficient for p65/RelA actually showed elevated levels of MCMV replication. Mutation of all NF-kappaB response elements within the enhancer of the MIEP in a recombinant mouse CMV containing the human MIEP (hMCMV-ES), which we have previously shown to replicate in murine fibroblasts with kinetics equivalent to that of wild-type mouse CMV, did not negatively affect replication in fibroblasts. Taken together, these data show that, for CMV replication in cultured fibroblasts activation of the canonical NF-kappaB pathway and binding of NF-kappaB to the MIEP are dispensable, and in the case of p65 may even interfere, thus uncovering a previously unrecognized level of complexity in the host regulatory network governing MIE gene expression in the context of a viral infection.
Benedict
Chris A
CA
La Jolla Institute of Allergy and Immunology, San Diego, California 92007, USA.
Angulo
Ana
A
Patterson
Ginelle
G
Ha
Sukwon
S
Huang
Huang
H
Messerle
Martin
M
Ware
Carl F
CF
Ghazal
Peter
P
D000818:Animals; D002478:Cells, Cultured; D003587:Cytomegalovirus / Q000378:metabolism*; D005347:Fibroblasts / Q000821:virology; D015967:Gene Expression Regulation, Viral; D006801:Humans; D017874:Immediate-Early Proteins / Q000378:metabolism; D008264:Macrophages / Q000821:virology; D051379:Mice; D018146:Muromegalovirus / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D020218:Response Elements; D051996:Transcription Factor RelA; D014158:Transcription, Genetic; D014779:Virus Replication
D017874:Immediate-Early Proteins; D016328:NF-kappa B; D051996:Transcription Factor RelA