Open AccessPositive control mutations in the MyoD basic region fail to show cooperative DNA binding and transcriptional activation in vitro.
Author(s) -
Eyal Bengal,
Osvaldo Flores,
Pundi N. Rangarajan,
Amy Chen,
Harold Weintraub,
Inder M. Verma
Publication year - 1994
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.91.13.6221
Subject(s) - myod , transcription factor , myod protein , transcription (linguistics) , dna , microbiology and biotechnology , biology , mutant , in vitro , binding site , myogenesis , genetics , gene , linguistics , philosophy
An in vitro transcription system from HeLa cells has been established in which MyoD and E47 proteins activate transcription both as homodimers and heterodimers. However, heterodimers activate transcription more efficiently than homodimers, and function synergistically from multiple binding sites. Positive control mutants in the basic region of MyoD that have previously been shown to be defective in initiating the myogenic program, can bind DNA but have lost their ability to function as transcriptional activators in vitro. Additionally, positive control mutants, unlike wild-type MyoD, fail to bind cooperatively to DNA. We propose that binding of MyoD complexes to high affinity MyoD binding sites induces conformational changes that facilitate cooperative binding to multiple sites and promote transcriptional activation.