Abstract
Silencing of ribosomal RNA genes (rDNA) requires binding of the chromatin remodelling complex NoRC to RNA that is complementary to the rDNA promoter. NoRC-associated RNA (pRNA) folds into a conserved stem-loop structure that is required for nucleolar localization and rDNA silencing. Mutations that disrupt the stem-loop structure impair binding of TIP5, the large subunit of NoRC, to pRNA and abolish targeting of NoRC to nucleoli. Binding to pRNA results in a conformational change of TIP5, as shown by enhanced sensitivity of TIP5 towards trypsin digestion. Our results indicate an RNA-dependent mechanism that targets NoRC to chromatin and facilitates the interaction with co-repressors that promote heterochromatin formation and rDNA silencing.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Base Sequence
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Cell Line
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Cell Nucleolus / metabolism*
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Chromatin / metabolism*
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Chromatin Assembly and Disassembly
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Chromosomal Proteins, Non-Histone / chemistry
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Chromosomal Proteins, Non-Histone / genetics
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Chromosomal Proteins, Non-Histone / metabolism*
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Electrophoretic Mobility Shift Assay
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Fluorescent Antibody Technique
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Humans
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Mice
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Molecular Sequence Data
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NIH 3T3 Cells
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Nucleic Acid Conformation
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Protein Binding
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Protein Conformation
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RNA / chemistry
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RNA / 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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Sequence Homology, Nucleic Acid
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Transcription, Genetic
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Transfection
Substances
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Baz2a protein, mouse
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Chromatin
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Chromosomal Proteins, Non-Histone
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Recombinant Fusion Proteins
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RNA