In the resulting abasic site, the cytosine is then correctly restored by base excision repair due to the guanine in the complementary strand.
UDG removes uracil bases from U:G mismatches in double-stranded DNA, generating abasic sites.
The bypass efficiency of DNA polymerases also differs markedly at abasic sites (36).
SSB Endo III sites, reflecting either abasic
sites or oxopyrimidines, were almost identical in both the exposed and control groups, but in contrast to our previous study (Somorovska et al.
AP endonuclease 1 (Ape1) is the major mammalian abasic endonuclease, accounting for > 95% of the total cellular AP site incision activity (Demple and Harrison 1994).
Using a 26-mer oligonucleotide duplex containing a single, centrally located abasic site analog--the F residue (Figure 1A)--we assessed the effects of several common environmental metals on Ape1 incision capacity.
Ape1 is a functional and structural homolog of ExoIII and belongs to this family of abasic endonucleases.
The critical differences are due to the properties of the DNA poly merase used and whether it can read through uracil and/or through abasic
The mechanism for this outcome is most likely an attack on DNA by induced increases in ROS formation; such toxicities can give rise to a variety of DNA lesions, including oxidized DNA bases, abasic
sites, and DNA strand-breaks.
Finally, we have recently described a combined PCR and sequencing method that, although useful for some applications, requires the use of a specially modified primer (containing an abasic
region and a long thymidine tail) and is somewhat limited in the length of sequencing data that can be generated (15).
In addition, the generation of alkali-labile abasic
sites might account for at least part of the persistent DNA damage in heart cells.
The mixture was incubated at 37[degrees]C for 3 h and then at 95[degrees]C for 30 min to denature DNA with abasic
sites and inactivate the uracil N-glycosylase and shrimp alkaline phosphatase.