Base excision repair in yeast and mammals

Base excision repair (BER), as initiated by at least seven different DNA gl ycosylases or by enzymes that cleave DNA at abasic sites, executes the repa ir of a wide variety of DNA damages. Many of these damages arise spontaneou sly because DNA interacts with the cellular milieu, and so BER profoundly i nfluences spontaneous mutation rates. In addition, BER provides significant protection against the toxic and mutagenic effects of DNA damaging agents present in the external environment, and as such is likely to prevent the a dverse health effects of such agents. BER pathways have been studied in a w ide variety of organisms (including yeasts) and here we review how these va ried studies have shaped our current view of human BER. (C) 2000 Published by Elsevier Science B.V.