Host: The Japanese Society of Toxicology
Name : The 50th Annual Meeting of the Japanese Society of Toxicology
Date : June 19, 2023 - June 21, 2023
Cells are exposed to various genomic stresses due to environmental factors such as ionizing radiation and chemicals. Because these genomic stresses trigger recovery from injury, cell death, and cellular senescence, it is important to understand and predict the effects of genomic stress on steady-state tissue homeostasis. DNA double-strand breaks (DSBs) are the most critical genomic stresses, which, if not repaired correctly, can lead to mutations and loss of function. We are developing a real-time and quantitative technique to analyze the DNA damage response induced by DSBs and its effects on the cell cycle, using concurrent live-cell imaging of 53BP1 protein, which aggregates at DSB sites during DSB repair, and proteins expressing cell-cycle indicators (hGmnn and hCdt1), named “Focicle”. We constructed a Focicle gene cassette and then generated a Focicle knock-in strain at ROSA26 region with CRISPR/Cas9 to establish a novel mouse model capable of quantitative live-cell imaging of cell-cycle dependent genomic stress. This mouse model enables us to observe radiation-induced induction and disappearance of DSB focus, and to construct organoids from organs of Focicle mouse for live-cell imaging. Furthermore, we are attempting to map DNA damage responses in whole-body by tissue clearing to facilitate imaging of genomic stress in all mouse tissues. We believe this is a useful model as a tool to understand tissue-level radiation and chemical-induced genomic stress responses in the whole body.
