Stimulated initiation of mitogen-activated protein kinase phosphatase-1 (MKP-1) gene transcription involves the synergistic action of multiple cis-acting elements in the proximal promoter.
Mitogen-activated protein kinases (MAPKs) are inactivated by a dual specificity phosphatase, MAPK phosphatase-1 (MKP-1). MKP-1 is transcribed as an immediate early response gene (IEG) following various stimuli. In the pituitary cell line GH4C1, MKP-1 gene transcription is strongly induced by thyrotropin-releasing hormone (TRH) as well as by epidermal growth factor (EGF) as a consequence of activated MAPK/extracellular-signal-regulated kinase (ERK) signalling. Intriguingly, reporter gene analysis with the MKP-1 promoter showed strong basal transcription, but only limited induction by TRH and EGF. Site-directed mutagenesis of the reporter construct combined with band-shift and in vivo studies revealed that part of the constitutive activity of the MKP-1 promoter resides in two GC boxes bound by Sp1 and Sp3 transcription factors in the minimal promoter. Basal transcription of transiently transfected luciferase reporter can be initiated by either of the two GC boxes or also by either of the two cAMP/Ca(2+) responsive elements or by the E-box present in the proximal promoter. On the other hand, when analysed by stable transfection, the five responsive elements are acting in synergy to transactivate the MKP-1 proximal promoter. We show in this study that the MKP-1 promoter can function as a constitutive promoter or as a rapid and transient sensor for the activation state of MAPKs/ERKs. This dual mode of transcription initiation may have different consequences for the control of a block to elongation situated in the first exon of the MKP-1 gene, as described previously [Ryser, Tortola, van Haasteren, Muda, Li and Schlegel (2001) J. Biol. Chem. 276, 33319-33327].
Ryser
Stephan
S
Fondation pour Recherche Médicales, University of Geneva, 64 av. de la Roseraie, 1211 Geneva, Switzerland.
Massiha
Abbas
A
Piuz
Isabelle
I
Schlegel
Werner
W
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D018797:Cell Cycle Proteins; D002460:Cell Line; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000378:metabolism; D054638:Dual Specificity Phosphatase 1; D004790:Enzyme Induction; D004815:Epidermal Growth Factor / Q000494:pharmacology; D020862:GC Rich Sequence; D017874:Immediate-Early Proteins / Q000096:biosynthesis / Q000235:genetics*; D020935:MAP Kinase Signaling System; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases; D011401:Promoter Regions, Genetic; D054645:Protein Phosphatase 1; D017027:Protein Tyrosine Phosphatases / Q000096:biosynthesis / Q000235:genetics*; D051381:Rats; D020218:Response Elements; D016329:Sp1 Transcription Factor / Q000378:metabolism; D051705:Sp3 Transcription Factor; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D017874:Immediate-Early Proteins; D016329:Sp1 Transcription Factor; C497123:Sp3 protein, rat; D014157:Transcription Factors; D051705:Sp3 Transcription Factor; D013973:Thyrotropin-Releasing Hormone; D004815:Epidermal Growth Factor; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D054638:Dual Specificity Phosphatase 1; C517021:Dusp1 protein, rat; D017027:Protein Tyrosine Phosphatases