DNA Polymerase α (swi7) and the Flap Endonuclease Fen1 (rad2) Act Together in the S-Phase Alkylation Damage Response in S. pombe
Figure 2
swi7-1 mutant might have a role in S-phase but not in mitotic checkpoint.
A. Images of the wt (JZ60), swi1 (E111), swi7-1 (JZ468) and cds1 (JZ475) cells stained with DAPI and Calcofluor were taken at 2.5 h and 5 h time point for both the untreated and MMS treated cultures. Gray arrows indicate cells with the cut phenotype. Five hundred or more cells were analyzed for each strain. B. Quantification of the percentage of cells displaying the “cut” phenotype and abnormal nuclei for the indicated strains, for both treated and untreated cultures. C. The swi7-1 mutant shows defect in S-phase progression in response to MMS damage. Asynchronous cultures of wt (JZ60), cds1 (JZ475), swi1 (E111) and swi7-1 (JZ468) strains were incubated in absence or presence of 0.01% or 0.03% MMS. Cell samples were taken for flow cytometry analysis at indicated time points. D. Mitosis index of wt, cds1, swi1 and swi7-1 cells. Changes in the percentage of binucleated and septated cells were determined as a function of time without and after the addition of 0.01% or 0.03% MMS.