Interferon consensus sequence-binding protein, a member of the interferon regulatory factor family, suppresses interferon-induced gene transcription.

Abstract

We previously isolated a cDNA clone encoding interferon consensus sequence-binding protein (ICSBP), a member of the interferon regulatory factor (IRF) (10,15,40,42,69,74). Recent genomic footprinting studies show that ISREs are constitutively occupied in vivo (19,56). IFN treatment leads to induction of multiple ISRE binding activities that differ in sensitivity to protein synthesis inhibitors (47, 74). One such IFN-inducible binding activity, ISGF3, is formed in the nucleus after translocation of preexisting components from the cytoplasm (45, 46). Inducible factor binding has been reported following virus induction of the IFN-13 gene as well (40,41).A number of laboratories have isolated cDNAs coding for proteins that bind to the ISRE. PRDI-BF1, a factor that binds to the virus-inducible element of the IFN-P gene, has been cloned by Keller and Maniatis (41

An IFN-γ-Inducible Transcription Factor, IFN Consensus Sequence Binding Protein (ICSBP), Stimulates IL-12 p40 Expression in Macrophages

“…As seen in lanes 1 and 2 of Fig. 4, B and D, GBP-ISRE promoter activity was stimulated by IFN-␥, but this stimulation was repressed by cotransfection of IRF-2 or ICSBP both in RAW and CL-2 cells (lanes 5-8), as would have been expected of their repressor function (18). These results show that ICSBP, but not IRF-1 or IRF-2, enhances IL-12 p40 promoter activity.…”

“…In light of a defect in IL-12 production reported for IRF-1 Ϫ/Ϫ mice (28, 29), we were interested in testing the activity of IRF-1. We also felt it important to test IRF-2, because ICSBP and IRF-2 repress transcription from IFN-␣␤-inducible promoters in a similar manner, suggesting a shared function by the two factors (18,38). Results are shown in Fig.…”

“…Deletion constructs were generated by PCR and sequenced by the dideoxy method. Expression vectors for ICSBP (pU5), IRF-1 (pACT-1), and IRF-2 (pACT-2) under the control of the ␤-actin promoter were described (18,32). All plasmids used for transfection assays were prepared by CsCl double banding to minimize endotoxin contamination.…”

Absence of p53-dependent cell cycle regulation in pluripotent mouse cell lines

“…Failure of radiation-induced p21 cip1 expression has been seen in cells lacking the transcription factor IRF-1 suggesting that elevated p53 levels may be insu cient to induce p21 cip1 expression. In fact, EC cells have been shown to express an antagonist of IRF-1 (Yamagata et al, 1996;Haggarty et al, 1991) that may be responsible for inhibiting induction of a variety of genes (Nelson et al, 1993).…”

Co-occupancy of the interferon regulatory element of the class II transactivator (CIITA) Type IV promoter by interferon regulatory factors 1 and 2

“…The interferon regulatory factor (IRF) family is composed of several structurally related proteins including IRF-1 (Harada et al, 1989;Pine et al, 1990), IRF-2 (Harada et al, 1989), ICSBP (Nelson et al, 1993), ISGF3g (Veals et al, 1992), IRF-3 (Grant et al, 1995), IRF-7 (Zhang and Pagano, 1997), Pip (Eisenbeis et al, 1995), and LSIRF (Yamagata et al, 1996), which play a vital role in the regulation of interferon (IFN)-and virus-mediated responses. IRF-1 and IRF-2 are generally regarded as a pair of mutually antagonizing transcription factors.…”