Fig. 2. chk1L
A mutants exhibit a loss-of-function phenotype. (A) UV survival was monitored for the indicated strains by a colony survival assay after exposure to 40, 80 or 160 J/m2 UV. Triplicate plates were prepared and the data represent the mean survival with error bars indicating the standard deviation. (B) Cells from the indicated strains were plated on YEA plates and incubated at 25°C, 32°C and 36°C to assay for synthetic lethality in a DNA ligase-deficient background cdc17-K42. (C) The indicated chk1 alleles were crossed into a cdc25-22 background in order to allow synchronization. G2-blocked cells were exposed to UV and released at 25°C. Cells were then scored for passage through mitosis (see Materials and Methods).