title: Methylation of an intragenic alternative promoter regulates transcription of GARP.
abstract: Alternative promoter usage has been proposed as a mechanism regulating transcriptional and translational diversity in highly elaborated systems like the immune system in humans. Here, we report that transcription of human glycoprotein A repetitions predominant (GARP) in regulatory CD4 T cells (Tregs) is tightly regulated by two alternative promoters. An intragenic promoter contains several CpGs and acts as a weak promoter that is demethylated and initiates transcription Treg-specifically. The strong up-stream promoter containing a CpG-island is, in contrast, fully demethylated throughout tissues. Transcriptional activity of the strong promoter was surprisingly down-regulated upon demethylation of the weak promoter. This demethylation-induced transcriptional attenuation regulated the magnitude of GARP expression and correlated with disease activity in rheumatoid arthritis. Treg-specific GARP transcription was initiated by synergistic interaction of forkhead box protein 3 (Foxp3) with nuclear factor of activated T cells (NFAT) and was underpinned by permissive chromatin remodeling caused by release of the H3K4 demethylase, PLU-1. Our findings describe a novel function of alternative promoters in regulating the extent of transcription. Moreover, since GARP functions as a transporter of transforming growth factor β (TGFβ), a cytokine with broad pleiotropic traits, GARP transcriptional attenuation by alternative promoters might provide a mechanism regulating peripheral TGFβ to avoid unwanted harmful effects.
authors.affiliation: Division of Rheumatology and Clinical Immunology, Medizinische Klinik und Poliklinik IV, University of Munich, 80336 Munich, Germany.
authors.forename: Sonja
authors.initials: S
authors.lastname: Haupt
authors.affiliation: Division of Rheumatology and Clinical Immunology, Medizinische Klinik und Poliklinik IV, University of Munich, 80336 Munich, Germany.
authors.forename: Viktoria Sophie Apollonia
authors.initials: VS
authors.lastname: Söntgerath
authors.affiliation: Division of Rheumatology and Clinical Immunology, Medizinische Klinik und Poliklinik IV, University of Munich, 80336 Munich, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Leipe
authors.affiliation: Division of Rheumatology and Clinical Immunology, Medizinische Klinik und Poliklinik IV, University of Munich, 80336 Munich, Germany.
authors.forename: Hendrik
authors.initials: H
authors.lastname: Schulze-Koops
authors.affiliation: Division of Rheumatology and Clinical Immunology, Medizinische Klinik und Poliklinik IV, University of Munich, 80336 Munich, Germany.
authors.forename: Alla
authors.initials: A
authors.lastname: Skapenko
mesh_terms: D042002:Chromatin Assembly and Disassembly / Q000235:genetics; D018899:CpG Islands; D019175:DNA Methylation / Q000235:genetics*; D051858:Forkhead Transcription Factors / Q000235:genetics*; D005786:Gene Expression Regulation; D006801:Humans; D056484:Jumonji Domain-Containing Histone Demethylases / Q000235:genetics; D019169:Jurkat Cells; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics*; D050778:NFATC Transcription Factors / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000235:genetics; D050378:T-Lymphocytes, Regulatory / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; C087215:LRRC32 protein, human; D008565:Membrane Proteins; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D012097:Repressor Proteins; D056484:Jumonji Domain-Containing Histone Demethylases; C119611:KDM5B protein, human
keywords: Alternative promoter; DNA methylation; GARP; Gene transcription; Transcriptional interference; Treg