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A protein domain conserved between yeast MCM1 and human SRF directs ternary complex formation
1Institute for Molecular Biology, Hannover Medical School, FRG.
The EMBO Journal
|December 1, 1991
Summary
MADS-box transcription factors MCM1 and SRF bind DNA and recruit other proteins. Specific amino acid changes in their shared domain alter protein interactions, revealing conserved structural bases for transcription factor complex formation.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- MADS-box proteins MCM1 and SRF bind to similar DNA sequences.
- They form transcription factor complexes with other proteins like STE12 and p62TCF.
Purpose of the Study:
- To investigate the molecular basis of specific protein-protein interactions in ternary complex formation.
- To identify the protein domains and amino acid residues responsible for differential recruitment of cofactors.
Main Methods:
- Gel retardation assays to study DNA-protein interactions.
- Site-directed mutagenesis to alter specific amino acid residues in MCM1 and SRF.
- Analysis of ternary complex formation with cofactors STE12 and p62TCF.
Main Results:
- A shared 90-amino acid domain in MCM1 and SRF is crucial for ternary complex formation, dimerization, and DNA binding.
- Mutational analysis revealed specific amino acid residues within this domain that dictate cofactor specificity.
- Exchanging key residues between ARG80 (related to SRF) and SRF, or between SRF and MCM1, altered their ability to recruit p62TCF and STE12, respectively.
Conclusions:
- Specific amino acids within a conserved domain of MADS-box transcription factors determine their interaction with distinct cofactors.
- The structural basis for these specific protein-protein interactions is evolutionarily conserved.
- This finding provides insights into the regulatory mechanisms of gene expression mediated by transcription factor complexes.