Southern blot showing RFLPs in F56 and V3. (A) Genomic DNA was isolated from slow-swimming insertional mutants, cut with PvuII, and analyzed by Southern blotting using the LC2 cDNA as a probe. This probe detects 0.9- and 3.5-kbp bands in most cell lines, including V5 and F55 (both containing a deletion of the ODA9 gene) and F57 (containing a disruption of an unidentified gene). However, both of these bands are missing in the F56 strain, and the lower band is missing in the V3 strain. (B) A probe (5′ End) specific for the 5′ UTR and entire coding region of the LC2 gene (see text) hybridizes to the upper band in DNA from both V5 and V3. A probe (3′ End) specific for the 3′ UTR of the LC2 gene hybridizes to the lower band in DNA from V5 but detects no band in DNA from V3, indicating that the deletion in V3 is at the 3′ end of the gene.