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.

*DNA Damage, *Transcription, Genetic, 0 (DNA, Complementary), 0 (DNA-Binding Proteins), 0 (Luminescent Proteins), 0 (Recombinant Fusion Proteins), 0 (xeroderma pigmentosum group A complementing protein), 147336-22-9 (green fluorescent protein), 148972-58-1 (ERCC6 protein), Active Transport, Cell Nucleus, Cell Line, Cell Nucleus/metabolism, Cells, Cultured, Cockayne Syndrome/metabolism, Computer Simulation, DNA Helicases/*chemistry/metabolism, DNA Repair, DNA, Complementary/metabolism, DNA-Binding Proteins/genetics, EC 2.7.7.- (RNA Polymerase II), EC 5.99.- (DNA Helicases), Fibroblasts/metabolism, Human, Image Processing, Computer-Assisted, Immunoblotting, Kinetics, Light, Luminescent Proteins/metabolism, Microscopy, Microscopy, Fluorescence, Protein Binding, RNA Polymerase II/chemistry, Recombinant Fusion Proteins/chemistry/metabolism, Software, Support, Non-U.S. Gov't, Time Factors, Ultraviolet Rays,
The Journal of Cell Biology
Erasmus MC: University Medical Center Rotterdam

van den Boom, V, Citterio, E, Hoogstraten, D, Zotter, A, van Cappellen, W.A, Hoeijmakers, J.H.J, … Vermeulen, W. (2004). DNA damage stabilizes interaction of CSB with the transcription elongation machinery. The Journal of Cell Biology, 166(1), 27–36. doi:10.1083/jcb.200401056