Cooperative interactions between the Caenorhabditis elegans homeoproteins UNC-86 and MEC-3.
The POU-type homeodomain protein UNC-86 and the LIM-type homeodomain protein MEC-3, which specify neuronal cell fate in the nematode Caenorhabditis elegans, bind cooperatively as a heterodimer to the mec-3 promoter. Heterodimer formation increases DNA binding stability and, therefore, increases DNA binding specificity. The in vivo significance of this heterodimer formation in neuronal differentiation is suggested by (i) a loss-of-function mec-3 mutation whose product in vitro binds DNA well but forms heterodimers with UNC-86 poorly and (ii) a mec-3 mutation with wild-type function whose product binds DNA poorly but forms heterodimers well.
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Department of Biological Sciences, Columbia University, New York, NY 10027.
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Chalfie
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins; D002454:Cell Differentiation; D004247:DNA / Q000378:metabolism*; D017238:Genes, Helminth; D005801:Genes, Homeobox; D015801:Helminth Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018398:Homeodomain Proteins; D060850:LIM-Homeodomain Proteins; D008969:Molecular Sequence Data; D009474:Neurons / Q000166:cytology; D009838:Oligodeoxyribonucleotides / Q000378:metabolism; D050809:POU Domain Factors; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D029742:Caenorhabditis elegans Proteins; D015801:Helminth Proteins; D018398:Homeodomain Proteins; D060850:LIM-Homeodomain Proteins; D009838:Oligodeoxyribonucleotides; D050809:POU Domain Factors; D014157:Transcription Factors; C072005:mec-3 protein, C elegans; C081539:unc-86 protein, C elegans; D004247:DNA