FIG. 7.

UDG-BER activities for MGC nuclear extracts prepared from 3-month-old (open) and 28-month-old (solid) male B6D2F₁ mice. Results are presented as means ± SEM of three replicate assays for each of three independent nuclear extract preparations. Results are for UDG-BER assays in which purified uracil-DNA glycosylase (a), DNA ligase III (b), β-pol (c), and DNA ligase I (d) were added to MGC nuclear extracts. ∗, significantly (P < 0.05) different from addition of 0 ng of protein within a specific age group.