Inducible cAMP Early Repressor Can Modulate Tyrosine Hydroxylase Gene Expression after Stimulation of cAMP Synthesis

• Published in: The Journal of biological chemistry 1996-10, Vol.271 (41), p.25375-25381
• Main Authors: Tinti, Cristina, Conti, Bruno, Cubells, Joseph F., Kim, Kwang-Soo, Baker, Harriet, Joh, Tong H.
• Format: Article
• Language: English
• Subjects: Activating Transcription Factors; Adrenal Glands - metabolism; Animals; Blood Proteins - biosynthesis; Blood Proteins - metabolism; Brain - metabolism; Chloramphenicol O-Acetyltransferase - biosynthesis; Cyclic AMP Response Element Modulator; Cyclic AMP Response Element-Binding Protein - biosynthesis; Cyclic AMP Response Element-Binding Protein - metabolism; DNA Primers; DNA-Binding Proteins - biosynthesis; DNA-Binding Proteins - metabolism; Gene Expression Regulation, Enzymologic - drug effects; Locus Coeruleus; Male; Neuroblastoma; PC12 Cells; Polymerase Chain Reaction; Rats; Rats, Sprague-Dawley; Repressor Proteins - biosynthesis; Repressor Proteins - metabolism; Reserpine - pharmacology; Transcription Factors - biosynthesis; Transcription Factors - metabolism; Transfection; Tyrosine 3-Monooxygenase - biosynthesis
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.271.41.25375

Members of the CREB/CREM/ATF family of transcription factors either enhance or repress transcription after binding to the cAMP response elements (CREs) of numerous genes. The rat gene for tyrosine hydroxylase (TH) bears a canonical CRE, at base pairs -38 through -45 from the transcription initiation site, that is essential for basal and cAMP-stimulated transcription (Kim, K.-S., Lee, M. K., Carroll, J., and Joh, T. H. (1993) J. Biol. Chem. 268, 15689-15695; Lazaroff, M., Patankar, S., Yoon, S. O., and Chikaraishi, D. M. (1995) J. Biol. Chem. 270, 21579-21589). The current study identifies CRE-binding proteins induced in pharmacological paradigms characterized by TH activation. PC12- and rat adrenal gland-derived nuclear proteins retarded a TH-CRE oligonucleotide in gel mobility shift assays with virtually identical patterns. These differed substantially from patterns exhibited by extracts from locus ceruleus or from neuroblastoma (SK-N-BE(2)C) and locus ceruleus-derived (CATH.a) cell lines. Forskolin stimulation of PC12 cells and reserpine treatment of rats increased, in nuclear extracts derived from cells and adrenal glands, respectively, the amount of a fast moving CRE/protein complex that was supershifted by an anti-CREM antibody. Subsequent Western, Northern, and polymerase chain reaction analyses indicated that a specific member of the CREM family, the inducible cAMP early repressor (ICER), was strongly induced in both systems. Cotransfection of PC12 cells with TH2400CAT plasmid and the expression vector pCMV-ICER-Ib demonstrated that ICER efficiently represses the transcriptional activity of the TH gene promoter. In addition, PKA-stimulated transcriptional activity of the promoter was effectively suppressed by ICER. These results suggest that ICER can modulate cAMP-stimulated transcription of the TH gene and provide a model accounting for rapid reversal of increased TH transcription following elevations in cAMP.