3-Methyladenine (3MeA) DNA glycosylase removes some forms of alkylated DNA bases and initiates the base excision
repair pathway to maintain genome integrity. Schizosaccharomyces pombe has two paralogues of 3MeA DNA glycosylase, Mag1p and Mag2p, which share homology with Escherichia coli AlkA and Saccharomyces cerevisiae Mag1p. A previous genetic study showed that both Mag1p and Mag2p are involved in the repair of damage caused by methyl
methanesulfonate (MMS). To clarify the biological function of these redundant enzymes, we performed complementation tests using E. coli alkA∆ and S. cerevisiae MAG1∆ cells. S. pombe Mag1p rendered these recipient cells
resistant to MMS to the same level as wild type cells. In contrast, Mag2p did not affect the sensitivity of alkA∆ and MAG1∆ cells to MMS. Mag2p may have evolved to function only in S. pombe cells separately from the known base excision repair pathway.
