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Collaborative interactions between MEF‐2 and Sp1 in muscle‐specific gene regulation
Author(s) -
Grayson Jason,
BasselDuby Rhonda,
Williams R. Sanders
Publication year - 1998
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/(sici)1097-4644(19980901)70:3<366::aid-jcb10>3.0.co;2-j
Subject(s) - enhancer , biology , transcription factor , microbiology and biotechnology , gene , biochemistry
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. J. Cell. Biochem. 70:366–375, 1998. © 1998 Wiley‐Liss, Inc.