Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Animals
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Base Sequence
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Caenorhabditis elegans / genetics
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Caenorhabditis elegans / metabolism*
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Caenorhabditis elegans Proteins*
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Cell Differentiation
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DNA / metabolism*
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Genes, Helminth
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Genes, Homeobox*
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Helminth Proteins / chemistry
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Helminth Proteins / genetics
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Helminth Proteins / metabolism*
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Homeodomain Proteins*
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LIM-Homeodomain Proteins
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Molecular Sequence Data
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Neurons / cytology
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Oligodeoxyribonucleotides / metabolism
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POU Domain Factors
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Promoter Regions, Genetic
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Transcription Factors / chemistry
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Transcription Factors / genetics
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Transcription Factors / metabolism*
Substances
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Caenorhabditis elegans Proteins
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Helminth Proteins
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Homeodomain Proteins
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LIM-Homeodomain Proteins
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Oligodeoxyribonucleotides
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POU Domain Factors
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Transcription Factors
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mec-3 protein, C elegans
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unc-86 protein, C elegans
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DNA