Dynamic and transient remodeling of the macrophage IL-10 promoter during transcription.
To gain insight into the molecular mechanism(s) whereby macrophages produce large amounts of IL-10, we analyzed IL-10 gene expression and temporally correlated it with modifications to chromatin associated with the IL-10 promoter. In resting cells, which make essentially no cytokines, the IL-10 promoter is associated with histones containing little or no detectable modifications. Macrophages stimulated in the presence of immune complexes begin to produce high levels of IL-10 pre-mRNA transcripts within minutes of stimulation. Coincident with this transcription was a rapid and dynamic phosphorylation of histone H3 at specific sites in the IL-10 promoter. Histone phosphorylation was closely followed by the binding of transcription factors to the IL-10 promoter. Blocking the activation of ERK prevented histone phosphorylation and transcription factor binding to the IL-10 promoter. In contrast to histone phosphorylation, the peak of histone acetylation at this promoter did not occur until after transcription had peaked. Inhibition of histone deactylase did not alter IL-10 gene expression, suggesting that phosphorylation but not acetylation was the proximal event responsible for IL-10 transcription. Our findings reveal a rapid and well-orchestrated series of events in which ERK activation causes a rapid and transient phosphorylation of histone H3 at specific regions of the IL-10 promoter, resulting in a transient exposure of the IL-10 promoter to the transcription factors that bind there. This exposure is essential for the efficient induction of IL-10 gene expression in macrophages. To our knowledge, this represents a unique way in which the expression of a cytokine gene is regulated in macrophages.
Zhang
Xia
X
Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA.
Edwards
Justin P
JP
Mosser
David M
DM
D000107:Acetylation; D000818:Animals; D001854:Bone Marrow Cells / Q000201:enzymology / Q000276:immunology / Q000378:metabolism; D002478:Cells, Cultured; D002843:Chromatin / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000502:physiology; D005786:Gene Expression Regulation / Q000276:immunology*; D006657:Histones / Q000378:metabolism; D016753:Interleukin-10 / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D007700:Kinetics; D008239:Lysine / Q000378:metabolism; D008264:Macrophages / Q000201:enzymology / Q000276:immunology* / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D010766:Phosphorylation; D011401:Promoter Regions, Genetic / Q000276:immunology*; D021381:Protein Transport / Q000235:genetics; D012694:Serine / Q000378:metabolism; D016329:Sp1 Transcription Factor / Q000378:metabolism; D013997:Time Factors
D002843:Chromatin; D006657:Histones; D016329:Sp1 Transcription Factor; D016753:Interleukin-10; D012694:Serine; D048049:Extracellular Signal-Regulated MAP Kinases; D008239:Lysine