FIG. 1.

Schematic representations of the construction of the cassette used to disrupt ssk1 (a) and the cassette SSK1-URA3-hisG, used to reintroduce one wild-type SSK1 allele (b). (c) Corresponding Southern blot analyses of strains CSSK11-1, CSSK12-1, CSSK21-1, and CSSK22-1, obtained during the disruption process, and a revertant strain (CSSK23-1). Genomic DNAs from these strains were BglII digested and hybridized with a 1.4-kb NsiI-EcoRI fragment located at the 5′ end of the SSK1 gene as a probe. The exact size and genotype of the expected hybridizing DNA fragments are indicated on the right. 5′-FOA, 5′-fluoro-orotic acid.