breaks after irradiation Iustinian Marina Martin Martina Mihail - - PowerPoint PPT Presentation

Detection and study of the formation and repair of DNA double-strand breaks after irradiation

Iustinian Mihail Focşa Marina Daniela Galiceanu Martin Dudr Martina Koncošová Supervisors:

• L. Ježková
• M. Zadneprianetc

Radiation is:

• ionizing, dangerous for living organisms
• non-ionizing, mostly harmless

The most harmful effect of the ionizing radiation is DNA damage. DNA DSBs are the most dangerous type of IR-induced DNA damage because it is hard to repair properly. Repair processes: Homologuous Recombination - error-free Non-Homologuous End Joining - error-prone, dominant in human cells

Effect of radiation on organisms

Human fibroblasts: cells mainly found in connective tissues that secrete collagen fibers DNA DSB

γH2AX protein signaling the damage 53BP1 protein involved in repair

primary antibody secondary antibodies with fluorescent dye

Immunostaining process

53BP1 signal γH2AX signal Mergence of the signals

Goal of the project: study of DSBs induction and repair in human fibroblasts under the effect of γ radiation Project motivation: fundamental research, applications in medicine and space exploration

Work in the laboratory

Simplified procedure

Cultivation of the fibroblast Irradiation (D = 1 Gy) Immunostaining of the cells at different times Image acquisition (take photos

• f the cells)

Data processing

Results

Distributions of frequency

Conclusions

• Maximum of γH2AX/53BP1 foci found 1 hour after gamma-irradiation

(1 Gy)

• 80% of foci disappeared in first 4 hours after irradiation
• After 1 day only 8% of foci were present
• DSB repair processes in human fibroblasts are considerably efficient

Thanks for your attention :-o