FIGURE 2:

Mutations in TUP1 suppress the growth defect of met4Δ. (A) We found two met4Δ-suppressed strains with mutations in the TUP1 gene (Table 2). The mutations (S697R and D699Y) are depicted in relation to the encoded Tup1p protein and its previously determined domains (Komachi and Johnson, 1997), and they are in a region of the protein that affects Tup1p interaction with transcription factors (Sprague et al., 2000). (B) Deletion of TUP1 causes a met4Δ haploid to grow significantly better. A met4Δ/MET4 tup1Δ/TUP1 diploid (DBY12232) was sporulated, and the resulting tetrads were dissected on YPD plates. The met4Δ tup1Δ cells remained methionine auxotrophs.