Figure 6.

Characterization of dominant mutant alleles of the SFA1 gene. (A) Formaldehyde (FA)-resistance phenotype in haploid (left) and heterozygous diploid (right) strains carrying three different mutant alleles of SFA1. The genotypes are indicated at the top. Serial dilutions were plated in media containing 0 or 1.5 mM FA as indicated to the left. No CuSO₄ was added. (B) Amino acid residue sequence alignment between the S. cerevisiae Sfa1p and the human FDH enzymes. Conserved residues (60.9% identity) are shown in black letters, and diverged residues are shown in gray. Shaded arrows point to the five residues that were substituted in the dominant SFA1 mutations.