Catalase T-Deficient Fission Yeast Meiocytes Show Resistance to Ionizing Radiation

Area of Science:

• Cell Biology
• Genetics
• Radiation Biology

Background:

• Environmental stressors like reactive oxygen species (ROS) and ionizing radiation (IR) cause DNA damage, potentially leading to mutations, cancer, or genetic diseases.
• DNA repair pathways and radical defense mechanisms are crucial for cellular resistance to genotoxic stress.
• Faulty DNA repair in germ cells can impact offspring development and health.

Purpose of the Study:

• To investigate the roles of cytosolic catalase T (Ctt1) and the Fe2+/Mn2+ symporter Pcl1 in protecting fission yeast (Schizosaccharomyces pombe) during meiosis.
• To understand their function in maintaining meiotic chromosome dynamics and gamete formation against ROS and IR-induced radicals.

Main Methods:

• Comparative analysis of wild-type, pcl1-deficient, and ctt1-deficient Schizosaccharomyces pombe strains.
• Exposure of meiocytes to varying doses of X-rays and hydrogen peroxide (H2O2).
• Assessment of cell survival rates and sensitivity to genotoxic stresses.

Main Results:

• Wild-type and pcl1-deficient cells exhibited similar responses to X-ray doses up to 300 Gy.
• ctt1∆ meiocytes showed moderate sensitivity to IR but hypersensitivity to H2O2, with cell death at >0.4 mM H2O2.
• pcl1-deficient meiocytes displayed H2O2 resistance comparable to wild-type cells, surviving doses >40 mM.

Conclusions:

• The primary H2O2-detoxifying enzyme, Ctt1, is essential for protecting S. pombe meiocytes against hydrogen peroxide.
• While Ctt1 is crucial for H2O2 resistance, S. pombe meiocytes can tolerate significant IR-induced radicals even in its absence.
• Pcl1 does not play a critical role in protecting S. pombe meiocytes from H2O2-induced stress.