Rad53- and Chk1-Dependent DNA Damage Response Pathways Cooperatively Promote Fungal Pathogenesis and Modulate Antifungal Drug Susceptibility

To elucidate the signaling circuitry downstream of Rad53, we compared transcriptome profiles between wild type and rad53Δ mutant strains post radiation exposure using RNAseq analysis. Of total 6,962 genes, 5,087 and 4,768 genes showed statistically different expression levels in the wild type and rad53Δ mutant strains, respectively, post radiation exposure (P-value cutoff of < 0.05; false decrease rate (FDR) cutoff of < 0.05). In the wild type strain, 392 genes exhibited ≥ 2-fold expression changes post radiation exposure To investigate downstream genes regulated by Rad53, total RNA was isolated from the wild-type (H99) and rad53∆ mutant. Strains were grown in a 40 ml liquid YPD medium for 16 hr at 30℃. Then, overnight culture was inoculated into 100 ml fresh YPD medium and adjusted to OD600=0.2. The cells were further incubated until OD600 reached approximately 0.6. Fifty ml of cells were pelleted for the zero-time sample and the remaining cells were exposed to γ-radiation (0.5 kGy). After γ-radiation exposure, cells were further incubated at 30℃ for 30 mins.