Local action of long-range repressors in the Drosophila embryo.
Previous studies have identified two corepressors in the early Drosophila embryo: Groucho and dCTBP: Both proteins are recruited to the DNA template by interacting with short peptide motifs conserved in a variety of sequence-specific transcriptional repressors. Once bound to DNA, Groucho appears to mediate long-range repression, while dCtBP directs short-range repression. The short-range Krüppel repressor was converted into a long-range repressor by replacing the dCtBP interaction motif (PxDLSxH) with a Groucho motif (WRPW). The resulting chimeric repressor causes a different mutant phenotype from that of the native Krüppel protein when misexpressed in transgenic embryos. The different patterning activities can be explained on the basis of long-range silencing within the hairy 5' regulatory region. The analysis of a variety of synthetic transgenes provides evidence that Groucho-dependent long-range repressors do not always cause the dominant silencing of linked enhancers within a complex cis-regulatory region. We suggest a "hot chromatin" model, whereby repressors require activators to bind DNA.
Nibu
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Y
Department of Molecular Cell Biology, Division of Genetics and Development, 401 Barker Hall, University of California, Berkeley, CA 94720, USA.
Zhang
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H
Levine
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M
D000429:Alcohol Oxidoreductases; D020816:Amino Acid Motifs / Q000502:physiology; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D019521:Body Patterning / Q000235:genetics; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004330:Drosophila; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D020868:Gene Silencing; D005799:Genes, Dominant; D019476:Insect Proteins / Q000235:genetics; D051741:Kruppel-Like Transcription Factors; D008957:Models, Genetic; D010641:Phenotype; D010750:Phosphoproteins / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000235:genetics; D019076:Transgenes
D000429:Alcohol Oxidoreductases; D051792:Basic Helix-Loop-Helix Proteins; D004247:DNA; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D051741:Kruppel-Like Transcription Factors; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; C497244:Kr protein, Drosophila; C091023:gro protein, Drosophila; C489235:hairy protein, Drosophila; C000604451:sna protein, Drosophila; C061841:hairy protein, insect; C096794:C-terminal binding protein