FIG. 7.

Construction of deletions of yeast DSS1 genes. (A) S. cerevisiae DSS1 deletion. The 5′ and 3′ genomic fragments flanking the DSS1 gene which were used in the deletion construct, shown in the wild-type and Δdss1 arrangements, with the extent of the deletion in nucleotides indicated beneath in kilobases. Haploid clones derived by sporulation of cells transformed with the deletion cassette were analyzed for DSS1 status by PCR on genomic DNA. Positions of forward and reverse primers 1 and 2 in the genomic sequences flanking those used in the deletion cassette are indicated in the upper panel with the expected size of the PCR product for wild-type or deleted clones. PCR results for three tetrads (3.1, 3.2, and 3.3) and the parent strain are shown at the bottom. (B) S. pombe dss1 deletion cassette, illustrating the 5′ and 3′ genomic fragments used to construct the deletion cassette, in both wild-type and Δdss1 configurations. Confirmation of the deletion by PCR is shown at the bottom.