This Article Full Text (PDF) Other Versions of this Article: MCB.00980-07v1 28/7/2446    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Franko, A. Articles by Goffart, S. Search for Related Content PubMed PubMed Citation Articles by Franko, A. Articles by Goffart, S.

 Previous Article  |  Next Article 

Mol. Cell. Biol. doi:10.1128/MCB.00980-07
Copyright (c) 2008, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.

CREB-1 is recruited to and mediates upregulation of the Cytochrome c promoter during enhanced mitochondrial biogenesis accompanying skeletal muscle differentiation

Institute of Vegetative Physiology, Medical Faculty, University of Köln, Germany; Center for Molecular Medicine Cologne (CMMC), University of Köln, Germany; Department of Medical Biochemistry and Molecular Biology, University of Saarland Medical Center, Homburg, Germany; and Unité de Biochimie et Biologie Cellulaire, University of Namur (FUNDP), Belgium

^* To whom correspondence should be addressed. Email: rudolf.wiesner{at}uni-koeln.de.

	Abstract

To further understand pathways coordinating the expression of nuclear genes encoding mitochondrial proteins, we studied mitochondrial biogenesis during differentiation of myoblasts to myotubes. This energy demanding process was accompanied by a 5-fold increase of ATP-turnover, covered by an 8-fold increase of mitochondrial activity. While no change in mtDNA copy number was observed, mRNAs as well as proteins for nuclear encoded Cytochrome c, Cytochrome c oxidase subunit IV and mitochondrial transcription factor A (TFAM) increased, together with total cellular RNA and protein levels. Detailed analysis of the Cytochrome c promoter by luciferase reporter, binding affinity and electrophoretic mobility shift assays as well as mutagenesis studies revealed a critical role for cAMP-responsive-element binding protein-1 (CREB-1) for promoter activation. Expression of two CREB-1 isoforms was observed using specific antibodies and quantitative RT-PCR, and a shift from phosphorylated CREB-1 in myoblasts to phosphorylated CREB-1 protein in myotubes was shown, while mRNA ratios remained unchanged. Chromatin immunoprecipitation assays confirmed preferential binding of CREB-1 in situ to the Cytochrome c promoter in myotubes. Overexpression of constitutively active and dominant negative forms supported the key role of CREB-1 in regulating expression of genes encoding mitochondrial proteins during myogenesis and probably also in other situations of enhanced mitochondrial biogenesis.