Photoaffinity labeling of mouse fibroblast enzymes by a base excision repair intermediate. Evidence for the role of poly(ADP-ribose) polymerase-1 in DNA repair.


To examine the interaction of mammalian base excision repair (BER) ...
To examine the interaction of mammalian base excision repair (BER) enzymes with DNA intermediates formed during BER, we used a novel photoaffinity labeling probe and mouse embryonic fibroblast cellular extracts. The probe was formed in situ, using an end-labeled oligonucleotide containing a synthetic abasic site; this site was incised by apurinic/apyrimidinic endonuclease creating a nick with 3'-hydroxyl and 5'-reduced sugar phosphate groups at the margins, and then a dNMP carrying a photoreactive adduct was added to the 3'-hydroxyl group. With near-UV light (312 nm) exposure of the extract/probe mixture, six proteins were strongly labeled. Four of these include poly(ADP-ribose) polymerase-1 (PARP-1) and the BER participants flap endonuclease-1, DNA polymerase beta, and apurinic/apyrimidinic endonuclease. The amount of the probe cross-linked to PARP-1 was greater than that cross-linked to the other proteins. The specificity of PARP-1 labeling was examined using various competitor oligonucleotides and DNA probes with alternate structures. PARP-1 labeling was stronger with a DNA representing a BER intermediate than with a nick in double-stranded DNA. These results indicate that proteins interacting preferentially with a photoreactive BER intermediate can be selected from the crude cellular extract.




new topics/pols set partial results complete validated


No results available for this paper.

Entry validated by:

Using Polbase tables:


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).


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.