A novel intronic promoter of the Crem gene induces small ICER (smICER) isoforms

Matthias D. Seidl*, Frank Nunes, Benedikt Fels, Iris Hildebrandt, Wilhelm Schmitz, Klaus Schulze-Osthoff, Frank U. Müller

*Corresponding author for this work
7 Citations (Scopus)


The transcription factors cAMP-responsive element binding protein (CREB) and cAMP-responsive element modulator (CREM) regulate gene transcription in response to elevated cAMP levels. The Crem isoform inducible cAMP early repressor (Icer) is transcribed by the internal promoter P2 as a critical regulator of multiple cellular processes. Here, we describe a novel inducible Crem isoform, small Icer (smIcer), regulated by a newly identified promoter (P6). ChIP revealed binding of CREB to P6 in human and mouse myocardium. P6 activity was induced by constitutively active CREB or stimulation of adenylyl cyclase. In mice, smIcer mRNA was ubiquitously expressed and transiently induced by β-adrenoceptor stimulation e.g., in heart and lung. SmICER repressed both basal and cAMP-induced activities of P6 and P2 promoters. Stimulation of adenylyl cyclase induced P2 and P6 in cell type-specific manner. Alternative translational start sites resulted in three different smICER proteins, linked to increased apoptosis sensitivity. In conclusion, the Crem gene provides two distinct and mutually controlled mechanisms of a cAMP-dependent induction of transcriptional repressors. Our results suggest not only that smICER is a novel regulator of cAMPmediated gene regulation, but also emphasize that biological effects that have been ascribed solely to ICER, should be revised with regard to smICER.

Original languageEnglish
JournalFASEB Journal
Issue number1
Pages (from-to)143-152
Number of pages10
Publication statusPublished - 01.2014

Research Areas and Centers

  • Academic Focus: Center for Brain, Behavior and Metabolism (CBBM)


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