caa a22 4500 445812915 CHVBK 20180317145217.0 cr unu---uuuuu 170323e20110801xx s 000 0 eng 10.1007/s00411-011-0366-9 doi (NATIONALLICENCE)springer-10.1007/s00411-011-0366-9 53BP1 and MDC1 foci formation in HT-1080 cells for low- and high-LET microbeam irradiations [Elektronische Daten] [Marita Mosconi, Ulrich Giesen, Frank Langner, Christian Mielke, Ilaria Dalla Rosa, Wilhelm Dirks] An improved assessment of the biological effects and related risks of low doses of ionizing radiation is currently an important issue in radiation biology. Irradiations using microbeams are particularly well suited for precise and localized dose depositions, whereas recombinant cell lines with fluorescent proteins allow the live observation of radiation-induced foci. Living cells of the fibrosarcoma cell line HT-1080 stably expressing 53BP1 or full-length reconstituted MDC1 fused to Green Fluorescent Protein (GFP) were irradiated with protons and α-particles of linear energy transfers (LETs) of 15and 75keV/μm, respectively. Using a microbeam, the irradiations were carried out in line patterns, which facilitated the discrimination between undefined background and radiation-induced foci. As expected, foci formation and respective kinetics from α-particle irradiations with a high LET of 75keV/μm could be detected in a reliable manner by both fusion proteins, as reported previously. Colocalization of γ-H2AX foci confirmed the DSB nature of the detected foci. As a novel result, the application of protons with low LET of 15keV/μm generated 53BP1- and MDC1-mediated foci of almost equal size and slightly different kinetics. This new data expands the capability of 53BP1 and wild-type MDC1 on visible foci formation in living cells after irradiation with low-LET particles. Furthermore, the kinetics in HT-1080 cells for α-particle irradiation show a delay of about 20s for 53BP1 foci detection compared to wild-type MDC1, confirming the hierarchical assembly of both proteins. Preliminary data for proton irradiations are shown and also these indicate a delay for 53BP1 versus MDC1. Springer-Verlag, 2011 Mosconi Marita Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany aut Giesen Ulrich Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany aut Langner Frank Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany aut Mielke Christian Heinrich Heine University (HHU), 40225, Düsseldorf, Germany aut Dalla Rosa Ilaria Heinrich Heine University (HHU), 40225, Düsseldorf, Germany aut Dirks Wilhelm Leibniz Institut Deutsche Sammlung für Mikroorganismen und Zellkulturen (DSMZ), 38124, Braunschweig, Germany aut Radiation and Environmental Biophysics Springer-Verlag 50/3(2011-08-01), 345-352 0301-634X 50:3<345 2011 50 411 https://doi.org/10.1007/s00411-011-0366-9 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00411-011-0366-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Mosconi Marita Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany aut NATIONALLICENCE 700 1- Giesen Ulrich Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany aut NATIONALLICENCE 700 1- Langner Frank Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany aut NATIONALLICENCE 700 1- Mielke Christian Heinrich Heine University (HHU), 40225, Düsseldorf, Germany aut NATIONALLICENCE 700 1- Dalla Rosa Ilaria Heinrich Heine University (HHU), 40225, Düsseldorf, Germany aut NATIONALLICENCE 700 1- Dirks Wilhelm Leibniz Institut Deutsche Sammlung für Mikroorganismen und Zellkulturen (DSMZ), 38124, Braunschweig, Germany aut NATIONALLICENCE 773 0- Radiation and Environmental Biophysics Springer-Verlag 50/3(2011-08-01), 345-352 0301-634X 50:3<345 2011 50 411 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer