title: Regulation of murine Tap1 and Lmp2 genes in macrophages by interferon gamma is mediated by STAT1 and IRF-1.
abstract: The genes of the transporter associated with antigen processing (Tap)-1, and the low molecular weight peptide (Lmp)-2, are crucial for class I major histocompatibility complex function and share a common bidirectional promoter. In murine bone marrow-derived macrophages, interferon gamma (IFN-gamma) induced Tap-1 and upregulated Lmp-2, which is constitutively expressed at low levels. The IFN-gamma-induction was independent of early gene synthesis. The mRNA induced by IFN-gamma was very stable. In macrophages from STAT1 knockout mice, IFN-gamma did not induce the expression of Tap-1 or Lmp-2. Several areas in the promoter can be controlled by IFN-gamma, such as proximal and distal GAS boxes in the direction of the Tap-1 gene, NFgammaB and IRF-1 boxes. By making deletions of the promoter, we found that only the proximal GAS and IRF-1 boxes are required for IFN-gamma induction of Tap-1 and Lmp-2. Experiments using nuclear extracts from macrophages treated for 30 min with IFN-gamma and gel shift analysis indicated that STAT1 binds to the GAS box. The nuclear extracts from macrophages treated for at least 2 h with IFN-gamma bound to the IRF-1 box. These results indicate that both STAT1 and IRF-1 are required for the IFN-gamma induction of Tap-1 and Lmp-2 genes.
authors.affiliation: Group of Macrophage Biology, Institute of Biomedical Research of Barcelona, Barcelona Science Park, University of Barcelona, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Brucet
authors.forename: L
authors.initials: L
authors.lastname: Marqués
authors.forename: C
authors.initials: C
authors.lastname: Sebastián
authors.forename: J
authors.initials: J
authors.lastname: Lloberas
authors.forename: A
authors.initials: A
authors.lastname: Celada
mesh_terms: D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000818:Animals; D002460:Cell Line; D003513:Cycloheximide / Q000494:pharmacology; D003546:Cysteine Endopeptidases / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D003609:Dactinomycin / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D050856:Interferon Regulatory Factor-1; D007371:Interferon-gamma / Q000494:pharmacology*; D007375:Interleukin-1 / Q000096:biosynthesis; D008262:Macrophage Activation / Q000187:drug effects / Q000235:genetics; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D010750:Phosphoproteins / Q000235:genetics*; D011401:Promoter Regions, Genetic; D050794:STAT1 Transcription Factor; D015534:Trans-Activators / Q000235:genetics*
chemical_list: D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D018528:ATP-Binding Cassette Transporters; D004268:DNA-Binding Proteins; D050856:Interferon Regulatory Factor-1; D007375:Interleukin-1; C494258:Irf1 protein, mouse; D010750:Phosphoproteins; D050794:STAT1 Transcription Factor; C494080:Stat1 protein, mouse; C073119:TAP1 protein, human; C486171:Tap1 protein, mouse; D015534:Trans-Activators; C071313:LMP-2 protein; D003609:Dactinomycin; D007371:Interferon-gamma; D003513:Cycloheximide; D003546:Cysteine Endopeptidases