Genetic interactions of SmD3 mutants. (A and B) Mutational synergies with mud1Δ and mud2Δ. Yeast smd3Δ strains bearing the indicated SMD3 allele on CEN LEU2 plasmid in an otherwise wild-type (panel A), mud1Δ (panel B) or mud2Δ (panel B) background were spot-tested for growth on YPD agar at the temperatures specified. (C) Bypass of prp28Δ. Yeast smd3Δ prp28Δ cells bearing wild-type SMD3 or SMD3-E37A-D38A on a CEN LEU2 plasmid and either p(CEN HIS3 PRP28) or an empty CEN HIS3 plasmid were grown in liquid culture at 37°C. After adjustment to the same cell density (by A₆₀₀), serial 10-fold dilutions were spotted to YPD agar. The plates were photographed after incubation for 2 d at 30, 34 and 37°C or 3 d at 25°C.