FIG. 2.

Phenotypic analysis of Bur1 alleles. (A) Temperature-sensitive alleles of bur1. Mutants were introduced by plasmid shuffling and then spotted onto yeast extract-peptone-dextrose (10-fold dilutions between each row). Plates were incubated at 30°C (2 days), 37°C (2 days), and 12°C (5 days). (B) Some Bur1 mutants are sensitive to 6AU (75 μg/ml) and MPA (15 μg/ml). Strains shown in panel A were further transformed with pRS316 (URA3⁺) and spotted onto synthetic complete medium (SC) plates with the indicated additions. (C) BUR1 mutant alleles display synthetic genetic interactions with ctk1Δ and spt5-194. Double mutant strains were created by mating and transformation as described elsewhere (Table 1). Cells were spotted onto SC plates ± 5-FOA to remove the wild-type BUR1 plasmid and grown for 2 days at 30°C.