Abstract
Previous investigations have demonstrated synergistic interactions in vivo between CCAC and A/T-rich nucleotide sequence motifs as functional components of muscle-specific transcriptional enhancers. Using CCAC and A/T- rich elements from the myoglobin and muscle creatine kinase (MCK) gene enhancers, Sp1 and myocyte-specific enhancer factor-2 (MEF-2) were identified as cognate binding proteins that recognize these sites. Physical interactions between Sp1 and MEF-2 were demonstrated by immunological detection of both proteins in DNA binding complexes formed in vitro by nuclear extracts in the presence of only the A/T sequence motif, by coprecipitation of recombinant MEF-2 in the presence of a glutathione-S-transferase-Sp1 fusion protein bound to glutathione beads, and by a two-hybrid assay in Saccharomyces cerevisiae. The interaction with Sp1 in vitro and in vivo is specific for MEF-2 and was not observed with serum response factor, a related MADS domain protein. Forced expression of Sp1 and MEF-2 in insect cells otherwise lacking these factors promotes synergistic transcriptional activation of a promoter containing binding sites for both proteins. These data expand the repertoire of functional and physical interactions between lineage-restricted (MEF-2) and ubiquitous (Sp1) transcription factors that may be important for myogenic differentiation.
Original language | English (US) |
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Pages (from-to) | 366-375 |
Number of pages | 10 |
Journal | Journal of Cellular Biochemistry |
Volume | 70 |
Issue number | 3 |
DOIs | |
State | Published - Sep 1 1998 |
Keywords
- DNA binding
- MADS domain
- Myogenesis
- Transcription
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology