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α-Actinin 4 and BAT1 interaction with the Cytochrome c promoter upon skeletal muscle differentiation
- Goffart, Steffi, Franko, Andras, Clemen, Christoph S., Wiesner, Rudolf J.
- Current genetics 2006 v.49 no.2 pp. 125-135
- DEAD-box RNA helicases, binding proteins, cell culture, cell differentiation, cytochrome c, databases, genes, heat shock proteins, muscle development, muscles, myoblasts, myotubes, rats, regulatory sequences, skeletal muscle, structural proteins
- To identify common regulatory features of nuclear genes encoding mitochondrial proteins we searched for regulatory elements in the Cytochrome c promoter during skeletal muscle differentiation in cell culture. A consensus element with the sequence GCTGCCGCAC-(N4-20)-GGSCGYGGG was found in both rat Cyt c and coxIV promoters. This new sequence element with yet undescribed function, but high abundance in promoters of nuclear genes encoding mitochondrial proteins available from the databases, showed a striking change in protein binding in electromobility shift assays when myoblasts were compared to myotubes. Proteins involved in the observed protein-DNA complexes were isolated from myotubes and identified by MALDI-TOF as BAT1, a DEAD-box protein of yet unknown function, heat shock protein HSP84, and α-actinin 4, a non-muscle isoform of the structural protein α-actinin. α-actinin 4 was found to be preferentially localized in the nucleus upon induction of myogenesis, suggesting a signaling function during muscle differentiation. In conclusion, the analyzed sequence motif may be a new candidate for common regulatory elements specific for nuclear encoded mitochondrial genes, and α-actinin 4 may be involved in their regulation.