AUF1 recognizes 8-oxo-guanosine embedded in DNA and stimulates APE1 endoribonuclease activity

ABSTRACT: The presence of rNMPs embedded in DNA represents a frequent genomic event able to destabilize the DNA backbone and to alter DNA replication and transcription. Usually, rNMPs are excised by RNase H2 and fully repaired by other enzymes belonging to the ribonucleotide excision repair pathway. The existence of modified rNMPs embedded in DNA, including 8-oxo-guanosine (8-oxo-G) and ribose monophosphate abasic site (rAP), have been recently highlighted by several works including ours. While eukaryotic RNase H2 is unable to process rAP and 8-oxo-G embedded in DNA, we demonstrated a role of APE1, a key enzyme of the base excision repair pathway, on these lesions. Notably, though APE1 activity on the repair of rAP sites results as efficient as the canonical dAP site, its incision repair activity on 8-oxo-G is very weak. Therefore, in order to guarantee an efficient repair activity of 8-oxo-G, additional processing mechanisms should be active in cells. In this work, by using an unbiased proteomic approach to isolate proteins able to recognize 8-oxo-G embedded in DNA, we discovered that AUF1 actively and specifically recognize 8-oxo-G and, interestingly, stimulates the APE1 enzymatic activity on this substrate. Although further structural analysis should be performed, it is reasonable that AUF1 facilitates the endoribonuclease activity of APE1 on 8-oxo-G by stabilizing the lesion substrate. Furthermore, by two orthogonal approaches including GST-pulldown and proximity ligation assay, we uncovered a novel protein-protein interaction between AUF1 and APE1. Remarkable, this interaction is modulated by H2O2-treatment, playing a putative biological role during cell response to oxidative stress.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): B Cell

SUBMITTER: Giovanni Renzone  

LAB HEAD: Andrea Scaloni

PROVIDER: PXD027252 | Pride | 2024-10-17

REPOSITORIES: Pride