The yeast MAT alpha 2 and MATa1 homeodomain proteins bind cooperatively as a heterodimer to sites upstream of haploid-specific genes, repressing their transcription. In the crystal structure of alpha 2 and a1 bound to DNA, each homeodomain makes independent base-specific contacts with the DNA and the two proteins contact each other through an extended tail region of alpha 2 that tethers the two homeodomains to one another. Because this extended region may be flexible, the ability of the heterodimer to discriminate among DNA sites with altered spacing between alpha 2 and a1 binding sites was examined. Spacing between the half sites was critical for specific DNA binding and transcriptional repression by the complex. However, amino acid insertions in the tail region of alpha 2 suppressed the effect of altering an a1/alpha 2 site by increasing the spacing between the half sites. Insertions in the tail also decreased DNA bending by a1/alpha 2. Thus tethering the two homeodomains contributes to DNA bending by a1/alpha 2, but the precise nature of the resulting bend is not essential for repression.
机构:
UNIV CALIF SAN FRANCISCO, DEPT BIOCHEM & BIOPHYS, SAN FRANCISCO, CA 94143 USAUNIV CALIF SAN FRANCISCO, DEPT BIOCHEM & BIOPHYS, SAN FRANCISCO, CA 94143 USA
DESPLAN, C
THEIS, J
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UNIV CALIF SAN FRANCISCO, DEPT BIOCHEM & BIOPHYS, SAN FRANCISCO, CA 94143 USAUNIV CALIF SAN FRANCISCO, DEPT BIOCHEM & BIOPHYS, SAN FRANCISCO, CA 94143 USA
THEIS, J
OFARRELL, PH
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h-index: 0
机构:
UNIV CALIF SAN FRANCISCO, DEPT BIOCHEM & BIOPHYS, SAN FRANCISCO, CA 94143 USAUNIV CALIF SAN FRANCISCO, DEPT BIOCHEM & BIOPHYS, SAN FRANCISCO, CA 94143 USA
机构:Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda
机构:
UNIV CALIF SAN FRANCISCO, DEPT BIOCHEM & BIOPHYS, SAN FRANCISCO, CA 94143 USAUNIV CALIF SAN FRANCISCO, DEPT BIOCHEM & BIOPHYS, SAN FRANCISCO, CA 94143 USA
DESPLAN, C
THEIS, J
论文数: 0引用数: 0
h-index: 0
机构:
UNIV CALIF SAN FRANCISCO, DEPT BIOCHEM & BIOPHYS, SAN FRANCISCO, CA 94143 USAUNIV CALIF SAN FRANCISCO, DEPT BIOCHEM & BIOPHYS, SAN FRANCISCO, CA 94143 USA
THEIS, J
OFARRELL, PH
论文数: 0引用数: 0
h-index: 0
机构:
UNIV CALIF SAN FRANCISCO, DEPT BIOCHEM & BIOPHYS, SAN FRANCISCO, CA 94143 USAUNIV CALIF SAN FRANCISCO, DEPT BIOCHEM & BIOPHYS, SAN FRANCISCO, CA 94143 USA
机构:Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda