title: Dynamics of the DNA repair proteins WRN and BLM in the nucleoplasm and nucleoli.
abstract: We have investigated the mobility of two EGFP-tagged DNA repair proteins, WRN and BLM. In particular, we focused on the dynamics in two locations, the nucleoli and the nucleoplasm. We found that both WRN and BLM use a "DNA-scanning" mechanism, with rapid binding-unbinding to DNA resulting in effective diffusion. In the nucleoplasm WRN and BLM have effective diffusion coefficients of 1.62 and 1.34 μm(2)/s, respectively. Likewise, the dynamics in the nucleoli are also best described by effective diffusion, but with diffusion coefficients a factor of ten lower than in the nucleoplasm. From this large reduction in diffusion coefficient we were able to classify WRN and BLM as DNA damage scanners. In addition to WRN and BLM we also classified other DNA damage proteins and found they all fall into one of two categories. Either they are scanners, similar to WRN and BLM, with very low diffusion coefficients, suggesting a scanning mechanism, or they are almost freely diffusing, suggesting that they interact with DNA only after initiation of a DNA damage response.
authors.affiliation: CMOL, Niels Bohr Institute, University of Copenhagen, 2100, Copenhagen, Denmark, kmoss@nbi.dk.
authors.forename: Kristian Moss
authors.initials: KM
authors.lastname: Bendtsen
authors.forename: Martin Borch
authors.initials: MB
authors.lastname: Jensen
authors.forename: Alfred
authors.initials: A
authors.lastname: May
authors.forename: Lene Juel
authors.initials: LJ
authors.lastname: Rasmussen
authors.forename: Ala
authors.initials: A
authors.lastname: Trusina
authors.forename: Vilhelm A
authors.initials: VA
authors.lastname: Bohr
authors.forename: Mogens H
authors.initials: MH
authors.lastname: Jensen
mesh_terms: D045744:Cell Line, Tumor; D002466:Cell Nucleolus / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D004058:Diffusion; D006801:Humans; D011485:Protein Binding; D021381:Protein Transport; D053484:RecQ Helicases / Q000378:metabolism*
chemical_list: D004247:DNA; C097151:Bloom syndrome protein; D053484:RecQ Helicases