Figure 1. Characterization of the mag2 Gene Function.

(A) Multiple-sequence alignment of S. pombe Mag1 and Mag2. Panel made using Jalview (Waterhouse et al., 2009) (B) Northern blot analysis of mag2 gene expression. Total RNA was isolated from untreated control (No) and from wildtype cells exposed to H₂O₂ or MMS and the filter was hybridized with a 642 bp mag2 probe. A β-a ctin (act1) probe was used as control. (C) Fluorescence microscopy of S. pombe cells expressing fusions of Mag2 to GFP. Yeast cells were transformed by DNA constructs expressing Mag2-GFPc (left panel) and stained with Hoechst 33342 as a nuclear marker (right panel). (D) MMS sensitivity of S. pombe BER mutant strains. S. pombe wild type (WT), mag1⁻, mag2⁻, apn2⁻, mag1⁻ apn2⁻ and mag2⁻ apn2⁻ mutant cells were spread on solid media containing increasing doses of MMS and cell survival was evaluated relative to plates without MMS. (E) Overexpression of Mag1, but not Mag2 is toxic for the fission yeast cells. S. pombe wild type (WT) and mag2⁻ mutant strains overexpressing Mag1 or Mag2 from pREP42 were spread on minimal media containing increasing doses of MMS and cell survival was evaluated relative to plates without MMS. Cells with empty vector (pREP42) were used as control. See also Figure S1.