Recognition of a DNA operator by a dimer composed of two different homeodomain proteins.
The yeast homeodomain proteins a1 and alpha 2 interact to form a heterodimer that binds DNA with high specificity. The DNA recognition element consists of two similar half sites, arranged with dyad symmetry and separated by a fixed number of base pairs. We demonstrate that in the a1 alpha 2-DNA complex, one of these half-sites is bound by a1 while the other is bound by alpha 2. These assignments allow a comparison of the chemical and nuclease protection patterns produced by both proteins when bound together to the hsg operator. Contrary to simple expectations, we propose that the a1 and alpha 2 homeodomains are arranged on the DNA in tandem, despite the fact that the recognition sequence is dyad symmetric.
Goutte
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Department of Biochemistry and Biophysics, University of California, San Francisco.
Johnson
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D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005801:Genes, Homeobox; D008969:Molecular Sequence Data; D009875:Operator Regions, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism
D004268:DNA-Binding Proteins; D004247:DNA