Poly(ADP-ribose) polymerase-1 (PARP-1) is required in murine cell lines for base excision repair of oxidative DNA damage in the absence of DNA polymerase beta.

Abstract:

Oxidative DNA base damage is mainly corrected by the base excision ...
Oxidative DNA base damage is mainly corrected by the base excision repair (BER) pathway, which can be divided into two subpathways depending on the length of the resynthetized patch, either one nucleotide for short patch BER or several nucleotides for long patch BER. The role of proteins in the course of BER processes has been investigated in vitro using purified enzymes and cell-free extracts. In this study, we have investigated the repair of 8-oxo-7,8-dihydroguanine (8-oxoG) in vivo using wild-type, polymerase beta(-/-) (Polbeta(-/-)), poly(ADP-ribose) polymerase-1(-/-) (PARP-1(-/-)), and Polbeta(-/-)PARP-1(-/-) 3T3 cell lines. We used non replicating plasmids containing a 8-oxoG:C base pair to study the repair of the lesion located in a transcribed sequence (TS) or in a non-transcribed sequence (NTS). The results show that 8-oxoG repair in TS is not significantly impaired in cells deficient in Polbeta or PARP-1 or both. Whereas 8-oxoG repair in NTS is normal in Polbeta-null cells, it is delayed in PARP-1-null cells and greatly impaired in cells deficient in both Polbeta and PARP-1. The removal of 8-oxoG and presumably the cleavage at the resulting apurinic/apyrimidinic site are not affected in the PARP-1(-/-)Polbeta(-/-) cell lines. However, 8-oxoG repair is incomplete, yielding plasmid molecules with a nick at the site of the lesion. Therefore, PARP-1(-/-)Polbeta(-/-) cell lines cannot perform 5'-dRP removal and/or DNA repair synthesis. Furthermore, the poly(ADP-ribosyl)ation activity of PARP-1 is essential for 8-oxoG repair in a Polbeta(-/-) context, because expression of the catalytically inactive PARP-1 (E988K) mutant does not restore 8-oxoG repair, whereas an wild type PARP-1 does.

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.