Abstract:
Exonucleolytic proofreading of DNA synthesis errors is one of the major determinants of
genome stability. However, many DNA transactions that contribute to genome stability require
synthesis by polymerases that naturally lack intrinsic 3´ exonuclease activity and some of which
are highly inaccurate. Here we discuss evidence that errors made by these polymerases may be
edited by a separate 3´ exonuclease, and we consider how such extrinsic proofreading may differ
from proofreading by exonucleases that are intrinsic to replicative DNA polymerases.