title: A distal locus element mediates IFN-γ priming of lipopolysaccharide-stimulated TNF gene expression.
abstract: Interferon γ (IFN-γ) priming sensitizes monocytes and macrophages to lipopolysaccharide (LPS) stimulation, resulting in augmented expression of a set of genes including TNF. Here, we demonstrate that IFN-γ priming of LPS-stimulated TNF transcription requires a distal TNF/LT locus element 8 kb upstream of the TNF transcription start site (hHS-8). IFN-γ stimulation leads to increased DNase I accessibility of hHS-8 and its recruitment of interferon regulatory factor 1 (IRF1), and subsequent LPS stimulation enhances H3K27 acetylation and induces enhancer RNA synthesis at hHS-8. Ablation of IRF1 or targeting the hHS-8 IRF1 binding site in vivo with Cas9 linked to the KRAB repressive domain abolishes IFN-γ priming, but does not affect LPS induction of the gene. Thus, IFN-γ poises a distal enhancer in the TNF/LT locus by chromatin remodeling and IRF1 recruitment, which then drives enhanced TNF gene expression in response to a secondary toll-like receptor (TLR) stimulus.
authors.affiliation: Program in Cellular and Molecular Medicine, Children's Hospital Boston, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Chow
authors.affiliation: Program in Cellular and Molecular Medicine, Children's Hospital Boston, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: Luke D
authors.initials: LD
authors.lastname: Jasenosky
authors.affiliation: Program in Cellular and Molecular Medicine, Children's Hospital Boston, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA. Electronic address: anne.goldfeld@childrens.harvard.edu.
authors.forename: Anne E
authors.initials: AE
authors.lastname: Goldfeld
mesh_terms: D000107:Acetylation; D001483:Base Sequence; D002460:Cell Line; D017124:Conserved Sequence; D015870:Gene Expression / Q000276:immunology; D056426:Genetic Loci; D006657:Histones / Q000378:metabolism; D006801:Humans; D050856:Interferon Regulatory Factor-1 / Q000378:metabolism; D007371:Interferon-gamma / Q000502:physiology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008969:Molecular Sequence Data; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D015533:Transcriptional Activation / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D006657:Histones; C494257:IRF1 protein, human; D050856:Interferon Regulatory Factor-1; D008070:Lipopolysaccharides; C439524:TNF protein, human; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma