FIGURE 4.

Trm112 and some of its partners display defects in oxidative stress tolerance. A, rich media cultures of strains PG111 (WT ctt1-GFP), JE48 (Δtrm112 ctt1-GFP), JE37 (Δmtq2 ctt1-GFP), JE39 (Δtrm9 ctt1-GFP), JE47 (Δtrm11 ctt1-GFP), and PG163 (Δbud23 ctt1-GFP) either untreated (Unt.) or treated with 1 mm H₂O₂ for 60 min were analyzed to determine Ctt1-GFP fluorescence level by flow cytometry. Results are expressed as a FITC/FCS ratio, normalized to the levels of untreated or treated wild-type cells, with an assigned value of 1. B, scheme illustrating tRNA modifications that require Trm112-methylase dimers. C, serial dilutions from cultures of strains 972 (WT), MS98 (Δatf1), JE34 (Δtrm112), JE23 (Δmtq2), JE25 (Δtrm9), JE33 (Δtrm11), and PG141 (Δbud23) were spotted onto rich plates without (YES) or with 2 mm and 5 mm of H₂O₂. D, arrest in the growth of strains 972 (WT), MS98 (Δatf1), JE34 (Δtrm112), JE23 (Δmtq2), and JE25 (Δtrm9) was calculated as described in Fig. 3B. A and D, S.D. were calculated from biological duplicates.