Interferon-gamma-activated STAT-1alpha suppresses MMP-9 gene transcription by sequestration of the coactivators CBP/p300.
Interferon-gamma (IFN-gamma) is a pleiotropic cytokine involved in aspects of immune regulation, cell proliferation, and host defense mechanisms directed toward various cancers. Some of the biological functions of IFN-gamma are achieved through inhibition of gene expression, although the mechanisms by which IFN-gamma suppresses gene transcription are poorly understood. Herein, we ... demonstrate the molecular basis by which IFN-gamma mediates suppression of the matrix metalloproteinase-9 (MMP-9) gene. IFN-gamma-activated signal transducer and activator of transcription-1alpha (STAT-1alpha) suppresses MMP-9 gene transcription, which is dependent on phosphorylation of tyrosine 701 but not phosphorylation of serine 727. The coactivator cyclic AMP response element-binding protein-binding protein (CBP) is an important component of induction of MMP-9 gene transcription. IFN-gamma induces the in vivo association of STAT-1alpha and CBP and decreases the association of CBP to the MMP-9 promoter. IFN-gamma does not influence the stability of CBP nor does IFN-gamma affect chromatin-remodeling events on the MMP-9 promoter. IFN-gamma inhibits the assembly of the MMP-9 transcription complex by suppressing H3/H4 acetylation and inhibiting recruitment of Pol II to the MMP-9 promoter. These findings indicate that IFN-gamma/STAT-1alpha exert their inhibitory effects by affecting multiple aspects of MMP-9 gene transcription.
Mesh Terms:
Acetylation, Antineoplastic Agents, CREB-Binding Protein, Chromatin Assembly and Disassembly, Cyclic AMP, DNA Polymerase II, Down-Regulation, Hela Cells, Histones, Humans, Interferon-Stimulated Gene Factor 3, Interferon-gamma, Matrix Metalloproteinase 9, Nuclear Proteins, Phosphorylation, Protein Processing, Post-Translational, Protein Transport, Response Elements, Second Messenger Systems, Trans-Activators, Transcription Factors
Acetylation, Antineoplastic Agents, CREB-Binding Protein, Chromatin Assembly and Disassembly, Cyclic AMP, DNA Polymerase II, Down-Regulation, Hela Cells, Histones, Humans, Interferon-Stimulated Gene Factor 3, Interferon-gamma, Matrix Metalloproteinase 9, Nuclear Proteins, Phosphorylation, Protein Processing, Post-Translational, Protein Transport, Response Elements, Second Messenger Systems, Trans-Activators, Transcription Factors
J. Leukoc. Biol.
Date: Aug. 01, 2005
PubMed ID: 15894584
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