8-oxoguanine incorporation into DNA repeats in vitro and mismatch recognition by MutSalpha.

Abstract:

DNA 8-oxoguanine (8-oxoG) causes transversions and is also implicated ...
DNA 8-oxoguanine (8-oxoG) causes transversions and is also implicated in frameshifts. We previously identified the dNTP pool as a likely source of mutagenic DNA 8-oxoG and demonstrated that DNA mismatch repair prevented oxidation-related frameshifts in mononucleotide repeats. Here, we show that both Klenow fragment and DNA polymerase alpha can utilize 8-oxodGTP and incorporate the oxidized purine into model frameshift targets. Both polymerases incorporated 8-oxodGMP opposite C and A in repetitive DNA sequences and efficiently extended a terminal 8-oxoG. The human MutSalpha mismatch repair factor recognized DNA 8-oxoG efficiently in some contexts that resembled frameshift intermediates in the same C or A repeats. DNA 8-oxoG in other slipped/mispaired structures in the same repeats adopted configurations that prevented recognition by MutSalpha and by the OGG1 DNA glycosylase thereby rendering it invisible to DNA repair. These findings are consistent with a contribution of oxidative DNA damage to frameshifts. They also suggest how mismatch repair might reduce the burden of DNA 8-oxoG and prevent frameshift formation.

Polymerases:

Topics:

Status:

new topics/pols set partial results complete validated

Results:

No results available for this paper.

Entry validated by:

Using Polbase tables:

Sorting:

Tables may be sorted by clicking on any of the column titles. A second click reverses the sort order. <Ctrl> + click on the column titles to sort by more than one column (e.g. family then name).

Filtering:

It is also possible to filter the table by typing into the search box above the table. This will instantly hide lines from the table that do not contain your search text.