A novel interferon-inducible domain: structural and functional analysis of the human interferon regulatory factor 1 gene promoter.

Abstract

We have cloned and functionally characterized the human interferon regulatory factor 1 (IRF-1) gene promoter. The promoter contains a CpG island, with several GC boxes, a CAAT box, but no TATA box. IRF-1 mRNA is strongly induced by gamma interferon (IFN-y) but more weakly and transiently by IFN-a. There are several putative KB motifs and numerous AA(G/A)G(G/T)A and GAAANN motifs throughout the promoter.The IRF-1 promoter is not autoregulated by the IRF-1 gene product. IFN inducibility of the promoter was studied with 5' deletion mutants linked to a heterologous reporter gene. Gel mobility shift assays were used to show IFN-inducible factor binding to the IRF-1 promoter. These studies showed that IFN inducibility is conferred by a novel imperfect inverted-repeat arrangement of two GAAANN motifs within a domain, 130 nucleotides upstream of transcription initiation. This inverted repeat binds a factor upon induction with IFN and can confer IFN inducibility on a heterologous promoter. Conversely, point mutations of the inverted repeat are not IFN inducible when linked to the same heterologous promoter.

Interleukin-12 Induces Expression of Interferon Regulatory Factor-1 via Signal Transducer and Activator of Transcription-4 in Human T Helper Type 1 Cells

“…Previous studies have demonstrated that induction of the IRF-1 gene in response to interferons and IL-6 is mediated by the binding of activated STAT-1 and STAT-3 to the palindromic GAS element present in the promoter of the IRF-1 gene (49,52,(57)(58)(59). In this report, we demonstrate that IL-12 induces IRF-1 gene transcription via activated STAT-4.…”

“…To analyze whether the IL-12-induced expression of IRF-1 is mediated by a specific STAT protein, we performed gel-shift experiments using a specific oligonucleotide corresponding to the GAS within the IRF-1 promoter (49,52). Total cell extracts were prepared from untreated Th1 and Th2 cells or from cells incubated with IL-12, IFN-␣, IFN-␥, and IL-4 and were used in gel-shift experiments shown in Fig.…”

Retinoic acid resistance in NB4 APL cells is associated with lack of interferon α synthesis Stat1 and p48 induction

“…It is unlikely that ISGF3 is formed after RA treatment and responsible for IFN induction, because RA is not able to stimulate the tyrosine phosphorylation of Stat1 (this paper and Matikainen et al, 1996). In addition to the GAS site (Pine et al, 1994), a putative NF-kB site has been found in the IRF-1 gene promoter (Sims et al, 1993). IFNg and TNF synergistically increase IRF-1 gene expression through the activation of Stat1 and NF-kB transcription factors respectively (Ohmori et al, 1997;Pine, 1997).…”

Genetic Polymorphism of Interferon-γ, Interferon-γ Receptor, and Interferon Regulatory Factor-1 Genes in Patients with Hepatitis B Virus Infection

“…Recently, the precise mechanism of binding between the interferon regulatory factor (IRF)-1 and IFN-stimulated response element (ISRE) has been clarified (Escalante et al, 1998). In addition, the promoter of the human IRF-1 gene has been isolated and characterized (Sims et al, 1993). The IRF-1 promoter is very rich in GC and contains various nuclear factor binding domains such as CpG islands, GC boxes, putative NF-jB binding sites, and many positive regulatory domains for IFNs.…”