Viral induction of the human beta interferon promoter: modulation of transcription by NF-kappa B/rel proteins and interferon regulatory factors.
Multiple regulatory domains within the -100 region of the beta interferon (IFN-beta) promoter control the inducible response of the IFN gene to virus infection. In this study, we demonstrate that the formation of NF-kappa B-specific complexes on the positive regulatory domain II (PRDII) precedes the onset of detectable IFN-beta transcription in Sendai virus-infected cells. By using NF-kappa B subunit-specific antibodies, a temporal shift in the composition of NF-kappa B subunits in association with the PRDII domain is detected as a function of time after virus infection. Furthermore, a virus-induced degradation of I kappa B alpha (MAD3) protein is observed between 2 and 8 h after infection; at later times, de novo synthesis of I kappa B alpha restores I kappa B alpha to levels found in uninduced cells and correlates with the down regulation of IFN-beta transcription. In cotransfection experiments using various NF-kappa B subunit expression plasmids and two copies of PRDII/NF-kappa B linked to a chloramphenicol acetyltransferase reporter gene, we demonstrate that expression of p65, c-Rel, or p50 or combinations of p50-p65 and p65-c-Rel differentially stimulated PRDII-dependent transcription. Coexpression of I kappa B alpha completely abrogated p65-, c-Rel-, or p65-p50-induced gene activity. When the entire IFN-beta promoter (-281 to +19) was used in coexpression studies, synergistic stimulation of IFN-beta promoter activity was obtained when NF-kappa B subunits were coexpressed together with the IFN regulatory factor 1 (IRF-1) transcription factor. Overexpression of either I kappa B or the IRF-2 repressor was able to abrogate inducibility of the IFN-beta promoter. Thus, multiple regulatory events--including differential activation of DNA-binding NF-kappa B heterodimers, degradation of I kappa B alpha, synergistic interaction between IRF-1 and NF-kappa B, and decreased repression by I kappa B and IRF-2--are all required for the transcriptional activation of the IFN-beta promoter.
Garoufalis
E
E
Terry Fox Molecular Oncology Group, Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital, Montreal, Quebec, Canada.
Kwan
I
I
Lin
R
R
Mustafa
A
A
Pepin
N
N
Roulston
A
A
Lacoste
J
J
Hiscott
J
J
D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D004247:DNA; D015870:Gene Expression; D006801:Humans; D016899:Interferon-beta / Q000235:genetics*; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism*; D010222:Parainfluenza Virus 1, Human / Q000502:physiology*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D020569:Proto-Oncogene Proteins c-rel; D012045:Regulatory Sequences, Nucleic Acid; D014158:Transcription, Genetic; D014779:Virus Replication
D016328:NF-kappa B; D011518:Proto-Oncogene Proteins; D020569:Proto-Oncogene Proteins c-rel; D016899:Interferon-beta; D004247:DNA