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Published on: February 7, 2019
The sequence specificity of homeodomain-DNA interaction
C Desplan1, J Theis, P H O'Farrell
1Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0448.
Cell
|September 23, 1988
Summary
The engrailed gene
Area of Science:
- Developmental biology
- Genetics
- Molecular biology
Background:
- The Drosophila melanogaster developmental gene, engrailed, is known to encode DNA binding activity.
- This activity is crucial for gene regulation during development.
Purpose of the Study:
- To identify the specific domain responsible for DNA binding in the engrailed gene.
- To characterize the DNA binding sites and specificity of the engrailed homeodomain.
- To compare the binding properties of the engrailed homeodomain with a related homeodomain.
Main Methods:
- Utilized deletion constructs of the engrailed gene.
- Expressed fusion proteins in E. coli for functional analysis.
- Determined DNA binding site consensus sequences.
- Performed binding assays and competition experiments.
Main Results:
- Localized the DNA binding activity to the conserved homeodomain (HD).
- Identified the binding site consensus as TCAATTAAAT, found in clusters in the engrailed regulatory region.
- Observed enhanced binding to adjacent copies of the consensus sequence.
- Found that the fushi tarazu (Ftz) homeodomain binds similar sites to engrailed (En) HD, with some differences in preference.
- Both En and Ftz HDs bind to a second sequence type: a repeat of TAA.
Conclusions:
- The similarity in sequence specificity between En and Ftz HDs suggests related DNA binding proteins share similar specificities.
- Competition among related regulatory proteins for binding sites may determine gene regulation outcomes.
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