Abstract
MAP kinase phosphatase-1 (MKP-1) controls nuclear MAP kinase activity with important consequences on cell growth or apoptosis. MKP-1 transcription is initiated constitutively but elongation is blocked within exon 1. It is unclear how induction of MKP-1 is controlled. Here, we report that the transcriptional elongation factors P-TEFb, DSIF and NELF regulate MKP-1 transcription in the pituitary GH4C1 cell line. Prior to stimulation, DSIF, NELF and RNA polymerase II (pol II) associate with the promoter-proximal region of the MKP-1 gene upstream of the elongation block site. Thyrotropin-releasing hormone (TRH) leads to recruitment of P-TEFb along the whole gene and a marked increase of DSIF and pol II downstream of the elongation block site, whereas NELF remains confined to the promoter-proximal region. 5,6-Dichloro-1-beta-d-ribofuranosylbenzimidazole (DRB) an inhibitor of P-TEFb eliminated TRH stimulation of MKP-1 transcription. DRB specifically inhibited TRH-induced recruitment of DSIF and P-TEFb to the MKP-1 gene. Furthermore, DRB treatment eliminated TRH-induced progression along the MKP-1 gene of pol II phosphorylated on Ser-2 of its CTD. These results indicate that P-TEFb is essential for gene-specific stimulated transcriptional elongation in mammalian cells via mechanisms which involve the activation of the DSIF-NELF complex and Ser-2 phosphorylation of pol II.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Cell Cycle Proteins / biosynthesis
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Cell Cycle Proteins / genetics*
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Cell Line
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Cyclin-Dependent Kinase 9 / antagonists & inhibitors
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Dichlororibofuranosylbenzimidazole / pharmacology
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Dual Specificity Phosphatase 1
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Enzyme Inhibitors / pharmacology
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Gene Expression Regulation, Enzymologic* / drug effects
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Immediate-Early Proteins / biosynthesis
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Immediate-Early Proteins / genetics*
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Models, Genetic
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Phosphoprotein Phosphatases / biosynthesis
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Phosphoprotein Phosphatases / genetics*
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Pituitary Gland / cytology
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Protein Phosphatase 1
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Protein Structure, Tertiary
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Protein Tyrosine Phosphatases / biosynthesis
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Protein Tyrosine Phosphatases / genetics*
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RNA Polymerase II / chemistry
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RNA Polymerase II / metabolism
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Rats
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Serine / metabolism
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Thyrotropin-Releasing Hormone / pharmacology
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Transcription Factors / metabolism
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Transcription, Genetic*
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Transcriptional Activation / drug effects
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Transcriptional Elongation Factors / antagonists & inhibitors
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Transcriptional Elongation Factors / metabolism*
Substances
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Cell Cycle Proteins
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Enzyme Inhibitors
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Immediate-Early Proteins
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Transcription Factors
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Transcriptional Elongation Factors
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negative elongation factor
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Serine
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Dichlororibofuranosylbenzimidazole
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Thyrotropin-Releasing Hormone
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Cyclin-Dependent Kinase 9
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RNA Polymerase II
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Phosphoprotein Phosphatases
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Protein Phosphatase 1
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Dual Specificity Phosphatase 1
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Dusp1 protein, rat
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Protein Tyrosine Phosphatases