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Fos, Jun and CREB basic-domain peptides have intrinsic DNA-binding activity enhanced by a novel stabilizing factor
1Unité 184 de Biologie Moléculaire et de Génie Génétique de l'INSERM, Faculté de Médecine, Strasbourg, France.
Oncogene
|October 1, 1990
Summary
The basic regions of transcription factors like Fos and Jun contain DNA-binding information, showing specific affinity for promoter elements like TRE and CRE. A novel protein, ABP, stabilizes these DNA-binding interactions.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Transcription factors with leucine zipper (LZ) domains bind DNA via adjacent basic regions.
- DNA-binding specificity is crucial for gene regulation.
Purpose of the Study:
- To determine if basic regions alone dictate DNA-binding specificity.
- To compare the binding affinities of different transcription factor basic domains to promoter elements.
Main Methods:
- Developed a competitive binding assay using synthetic peptides.
- Utilized HeLa cell nuclear extracts containing Fos/Jun and CREB.
- Assessed peptide affinity for TRE, CRE, Sp1, and octamer promoter sequences.
Main Results:
- Basic domains of Fos and Jun showed higher affinity for TRE and CRE compared to CREB.
- Peptides retained promoter selectivity, showing minimal affinity for Sp1 and octamer sequences.
- Identified a novel auxiliary bridging protein (ABP) that stabilizes Fos and Jun binding.
Conclusions:
- The basic region of transcription factors contains inherent DNA-binding specificity.
- Conserved features like dipolar arrangement and spacing of basic clusters are critical for binding.
- ABP plays a role in stabilizing protein-DNA complexes.