Fig. 2. Response to DNA damage of TEL1-overexpressing cells. Strains were as follows: wild type (K699), GAL1–MEC1 (YLL516), GAL1–TEL1 (DMP3539/10D) and GAL1–TEL1 GAL1–MEC1 (DMP3539/9D). (A) Dose–response killing curves were determined by plating serial dilutions of YEP-raf exponentially growing cell cultures on YEP-raf-gal plates with or without MMS or HU at the concentrations indicated. One set of YEP-raf-gal plates was exposed at the UV doses indicated. Plates were incubated at 25°C and colony-forming units were counted after 3 days. (B and C) Cell cultures growing logarithmically in YEP-raf were synchronized in G₁ with α-factor in the presence of galactose (2 h). Cells were released from the α-factor block at time zero in YEP-raf-gal, or were UV irradiated (40 J/m²) prior to release in YEP-raf-gal. Samples of untreated and UV-irradiated cultures were taken at the times indicated after α-factor release to analyze the DNA content by FACS (B) and to determine the level and phosphorylation of Rad53 by western blot analysis of protein extracts from the UV-treated cell cultures with anti-Rad53 antibodies (C). exp, exponentially growing cells.