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Multiple forms of formamidopyrimidine-DNA glycosylase
produced by alternative splicing in Arabidopsis thaliana
Terence M. Murphy1 and Ming-Jun Gao2
Section of Plant Biology, University of California, One
Shields Ave., Davis, CA 95616 USA
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
to: Terence M. Murphy, Section of Plant Biology, One Shields Avenue,
University of California, Davis, CA 95616; FAX +1 (530) 752-5410; e-mail email@example.com
Department of Agricultural, Food and Nutritional Science, University of Alberta,
Edmonton, AB, T6G 2P5 Canada
Abbreviations: fapy-A, 4,6-diamino-5-formamidopyrimidine; fapy-G, 2,6-diamino-4-hydroxy-5-formamidopyrimidine; FPG, formamidopyrimidine-DNA glycosylase; 8-oxo-G, 7,8-dihydro-8-oxoguanine.
The background image in this paper is a representation of human 8-oxo-G glycosylase (Bruner et al., 2000). This enzyme has an activity similar, but is not homologous, to FPG.