Recruitment Kinetics of XRCC1 and RNF8 Following MeV Proton and α-Particle Micro-Irradiation

Abstract

Time-lapse fluorescence imaging coupled to micro-irradiation devices provides information on the kinetics of DNA repair protein accumulation, from a few seconds to several minutes after irradiation. Charged-particle microbeams are valuable tools for such studies since they provide a way to selectively irradiate micrometric areas within a cell nucleus, control the dose and the micro-dosimetric quantities by means of advanced detection systems and Monte Carlo simulations and monitor the early cell response by means of beamline microscopy. We used the charged-particle microbeam installed at the AIFIRA facility to perform micro-irradiation experiments and measure the recruitment kinetics of two proteins involved in DNA signaling and repair pathways following exposure to protons and α-particles. We developed and validated image acquisition and processing methods to enable a systematic study of the recruitment kinetics of GFP-XRCC1 and GFP-RNF8. We show that XRCC1 is recruited to DNA damage sites a few seconds after irradiation as a function of the total deposited energy and quite independently of the particle LET. RNF8 is recruited to DNA damage sites a few minutes after irradiation and its recruitment kinetics depends on the particle LET.

Proton Microbeam Targeted Irradiation of the Gonad Primordium Region Induces Developmental Alterations Associated with Heat Shock Responses and Cuticle Defense in Caenorhabditis elegans

“…Worms were irradiated with 3 MeV protons delivered on the micro-irradiation setup installed on the AIFIRA facility (Applications Interdisciplinaires des Faisceaux d'Ions en Région Aquitaine, Bordeaux, France) [14,15]. The accelerator (Singletron TM , High Voltage Engineering Europa, Amersfoort, The Netherlands) delivers light ion beams with energies up to 3 MeV [33].…”

“…Extending this approach to charged-particle microbeams could help to characterize the specific radiationinduced biological responses. Charged-particle microbeams provide the possibility of selectively irradiating living cells with a precise dose and dose delivery timing [13][14][15][16][17][18]. Initially developed to target adherent mammalian cells, the use of charged-particle microbeams have progressively broadened to encompass the irradiation of three-dimensional tissue models and small in vivo multicellular system [19][20][21][22].…”