Fig. 1. Characterization of Csx1 as an oxidation-specific protein. (A) Serial dilutions (10⁴–10⁰) of wild-type, spc1Δ, 1F7 mutant and 9B8 mutant cultures were plated in rich medium (YES), rich medium with 0.8 M KCl (osmotic stress) and rich medium with 0.4 mM H₂O₂ (oxidative stress). Pictures were taken after incubation of the plates for 3–5 days at 30°C. (B) RNA recognition motif (RRM) conservation among Csx1, mammalian HuR and mammalian TIA-1. The numbers indicate the level of similarity. (C) Survival of wild-type, csx1Δ and spc1Δ under oxidative (1 mM H₂O₂) or osmotic (0.8 M KCl) stress. Cultures were incubated for the indicated times in the presence of stress and cells plated in rich medium (non-stress conditions). Colonies were counted after 3–5 days incubation at 30°C.