FIGURE 6.

Defects in Smc5/6 lead to elevated levels of unresolved recombination intermediates near the genomic ARS304 region after MMS treatment. A, representative two-dimensional gel analysis of replication intermediates at ARS304 (similar results were obtained at ARS305). WT, wild type. B, quantification of the ratio of X-shaped molecules to structures running within the replication arc. Data represent the mean ± S.E. (error bars) of three or more independent samples per genotype. Comparisons between wild type and mms21-sp, smc5-6, and smc6-9 values were all significant, p < 0.002. C, replication intermediates from two-dimensional gel analysis are shown, and the various species of interest are labeled. Branch migration assay shows control (nonbranch migrated), −Mg²⁺, and +Mg²⁺ (samples migrated in the absence or presence of magnesium) reactions. D, expression of Mms21 resolves X-spikes that have accumulated in mms21-sp mutants exposed to MMS (for details, see “Experimental Procedures”).