Abstract
The Cockayne syndrome B (CSB) protein is essential for transcription-coupled DNA repair (TCR), which is dependent on RNA polymerase II elongation. TCR is required to quickly remove the cytotoxic transcription-blocking DNA lesions. Functional GFP-tagged CSB, expressed at physiological levels, was homogeneously dispersed throughout the nucleoplasm in addition to bright nuclear foci and nucleolar accumulation. Photobleaching studies showed that GFP-CSB, as part of a high molecular weight complex, transiently interacts with the transcription machinery. Upon (DNA damage-induced) transcription arrest CSB binding these interactions are prolonged, most likely reflecting actual engagement of CSB in TCR. These findings are consistent with a model in which CSB monitors progression of transcription by regularly probing elongation complexes and becomes more tightly associated to these complexes when TCR is active.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Active Transport, Cell Nucleus
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Cell Line
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Cell Nucleus / metabolism
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Cells, Cultured
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Cockayne Syndrome / metabolism
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Computer Simulation
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DNA Damage*
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DNA Helicases / chemistry*
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DNA Helicases / metabolism
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DNA Repair
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DNA Repair Enzymes
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DNA, Complementary / metabolism
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DNA-Binding Proteins / genetics
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Fibroblasts / metabolism
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Green Fluorescent Proteins
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Humans
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Image Processing, Computer-Assisted
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Immunoblotting
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Kinetics
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Light
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Luminescent Proteins / metabolism
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Microscopy
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Microscopy, Fluorescence
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Poly-ADP-Ribose Binding Proteins
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Protein Binding
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RNA Polymerase II / chemistry
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / metabolism
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Software
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Time Factors
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Transcription, Genetic*
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Ultraviolet Rays
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Xeroderma Pigmentosum Group A Protein
Substances
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DNA, Complementary
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DNA-Binding Proteins
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Luminescent Proteins
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Poly-ADP-Ribose Binding Proteins
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Recombinant Fusion Proteins
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XPA protein, human
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Xeroderma Pigmentosum Group A Protein
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Green Fluorescent Proteins
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RNA Polymerase II
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DNA Helicases
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ERCC6 protein, human
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DNA Repair Enzymes