FIG. 1.

Disruption of spn and pik1 genes. Gray arrows represent the genomic coding regions (including introns, where present) of the indicated genes; the total number of base pairs in each coding region (from the first base of the start codon to the last base of the stop codon) is indicated. Black arrows (not drawn to scale) represent the ura4⁺ and LEU2 marker cassettes (see Materials and Methods), which were inserted after cutting of the original plasmids at the indicated sites, ligation to HindIII linkers, and digestion with HindIII. Sites indicated below the gray arrows were used to release the fragments used for transformation; the XhoI sites used with spn1 and spn2 were included in the primers used to clone these genes (Table 2).