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Comparison of DNA-binding properties between BTEB and Sp1
K Sogawa1, Y Kikuchi, H Imataka
1Department of Chemistry, Faculty of Science, Tohoku University, Sendai.
Journal of Biochemistry
|October 1, 1993
Summary
The study shows that BTEB and Sp1 proteins bind to the same DNA region, a GC box, with similar sequence specificity and binding affinity. This suggests comparable DNA binding mechanisms for these transcription factors.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Transcription factors BTEB and Sp1 play roles in gene regulation.
- Understanding their DNA-binding properties is crucial for deciphering gene expression mechanisms.
Purpose of the Study:
- To investigate and compare the DNA-binding properties of BTEB and Sp1.
- To determine the sequence specificity and binding affinity of BTEB.
Main Methods:
- Expression of truncated BTEB and Sp1 proteins in E. coli.
- Ortho-phenanthroline-Cu footprinting to identify DNA binding regions.
- Methylation interference footprinting to pinpoint specific nucleotide interactions.
- Competitive gel mobility shift assays to assess sequence specificity.
- Gel mobility shift assay to measure dissociation constant.
Main Results:
- Both BTEB and Sp1, along with their chimeric forms, protected the same GC box region in the BTE sequence.
- Methylation interference revealed interactions with guanines within and near the GC box.
- Competitive assays demonstrated similar sequence specificities for BTEB and Sp1.
- Purified BTEB exhibited a dissociation constant comparable to Sp1 for GC box binding.
Conclusions:
- BTEB and Sp1 bind to the GC box with similar sequence specificities.
- The binding modes of BTEB and Sp1 to the GC box are comparable.
- BTEB exhibits high-affinity DNA binding similar to Sp1.