title: The non-homologous end-joining (NHEJ) mathematical model for the repair of double-strand breaks: II. Application to damage induced by ultrasoft X rays and low-energy electrons.
abstract: We investigated the kinetics of simple and complex types of double-strand breaks (DSB) using our newly proposed mechanistic mathematical model for NHEJ DSB repair. For this purpose the simulated initial spectrum of DNA DSB, induced in an atomistic canonical model of B-DNA by low-energy single electron tracks, 100 eV to 4.55 keV, and the electrons generated by ultrasoft X rays (CK, AlK and TiK), were subjected to NHEJ repair processes. The activity elapsed time of sequentially independent steps of repair performed by proteins involved in NHEJ repair process were calculated for separate DSB. The repair kinetics of DSBs were computed and compared with published data on repair kinetics obtained by pulsed-field gel electrophoresis method. The comparison shows good agreement for V79-4 cells irradiated with ultrasoft X rays. The average times for the repair of simple and complex DSB confirm that double-strand break complexity is a potential explanation for the slow component of DSB repair observed in V79-4 cells irradiated by ultrasoft X rays.
authors.affiliation: Radiation Biophysics Group, Department of Oncology- Pathology, Karolinska Institutet, Stockholm SE171 76, Sweden.
authors.forename: Reza
authors.initials: R
authors.lastname: Taleei
authors.forename: Peter M
authors.initials: PM
authors.lastname: Girard
authors.forename: Krishnaswami
authors.initials: K
authors.lastname: Sankaranarayanan
authors.forename: Hooshang
authors.initials: H
authors.lastname: Nikjoo
mesh_terms: D001483:Base Sequence; D002244:Carbon / Q000009:adverse effects; D053903:DNA Breaks, Double-Stranded / Q000528:radiation effects*; D059766:DNA End-Joining Repair / Q000528:radiation effects*; D004583:Electrons / Q000009:adverse effects*; D007700:Kinetics; D008957:Models, Genetic; D014965:X-Rays / Q000009:adverse effects
chemical_list: D002244:Carbon