Abstract
In the early Caenorhabditis elegans embryo, maternally expressed PIE-1 protein is required in germ-line blastomeres to inhibit somatic differentiation, maintain an absence of mRNA transcription, and block phosphorylation of the RNA polymerase II large subunit (Pol II) carboxy-terminal domain (CTD). We have determined that PIE-1 can function as a transcriptional repressor in cell culture assays. By fusing PIE-1 sequences to the yeast GAL4 DNA-binding domain, we have identified a PIE-1 repression domain that appears to inhibit the transcriptional machinery directly. A sequence element that is required for this repressor activity is similar to the Pol II CTD heptapeptide repeat, suggesting that the PIE-1 repression domain might target a protein complex that can bind the CTD. An alteration of this sequence element that blocks repression also impairs the ability of a transgene to rescue a pie-1 mutation, suggesting that this repressor activity may be important for PIE-1 function in vivo.
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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Animals, Genetically Modified
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Caenorhabditis elegans / embryology
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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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Genes, Reporter
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Germ Cells / metabolism
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HeLa Cells
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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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Humans
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Molecular Sequence Data
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Mutation
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Nuclear Proteins / chemistry
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism*
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Phosphorylation
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RNA Polymerase II / antagonists & inhibitors*
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RNA Polymerase II / chemistry
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RNA Polymerase II / metabolism
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Repressor Proteins / chemistry
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Repressor Proteins / genetics
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Repressor Proteins / metabolism*
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Sequence Alignment
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Transcription, Genetic*
Substances
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Caenorhabditis elegans Proteins
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Helminth Proteins
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Nuclear Proteins
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Recombinant Fusion Proteins
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Repressor Proteins
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pie-1 protein, C elegans
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RNA Polymerase II