Multiple forms of formamidopyrimidine-DNA glycosylase produced by alternative splicing in Arabidopsis thaliana.

Formamidopyrimidine-DNA glycosylase (FPG) catalyzes the initial steps in the repair of DNA containing oxidized purines. Two cDNA clones from Arabidopsis thaliana encoding homologs of bacterial FPG have previously been described. We now report that there are at least five additional variants of FPG mRNA in Arabidopsis, each apparently produced from the same gene (AtMMH) by alternative splicing. Thus, AtMMH, like at least four other genes in the base excision repair pathway of human cells, produces multiple forms of protein product through alternative splicing. The variant forms of Arabidopsis FPG may be localized in different locations in the cells, may have different preferences for oxidized substrates, and/or may recruit different proteins that guide the subsequent steps of base excision repair.