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RPA2 winged-helix domain facilitates UNG-mediated removal of uracil from ssDNA; implications for repair of mutagenic uracil at the replication fork
- Source :
- Nucleic Acids Research
- Publication Year :
- 2021
-
Abstract
- Uracil occurs at replication forks via misincorporation of deoxyuridine monophosphate (dUMP) or via deamination of existing cytosines, which occurs 2–3 orders of magnitude faster in ssDNA than in dsDNA and is 100% miscoding. Tethering of UNG2 to proliferating cell nuclear antigen (PCNA) allows rapid post-replicative removal of misincorporated uracil, but potential ‘pre-replicative’ removal of deaminated cytosines in ssDNA has been questioned since this could mediate mutagenic translesion synthesis and induction of double-strand breaks. Here, we demonstrate that uracil-DNA glycosylase (UNG), but not SMUG1 efficiently excises uracil from replication protein A (RPA)-coated ssDNA and that this depends on functional interaction between the flexible winged-helix (WH) domain of RPA2 and the N-terminal RPA-binding helix in UNG. This functional interaction is promoted by mono-ubiquitination and diminished by cell-cycle regulated phosphorylations on UNG. Six other human proteins bind the RPA2-WH domain, all of which are involved in DNA repair and replication fork remodelling. Based on this and the recent discovery of the AP site crosslinking protein HMCES, we propose an integrated model in which templated repair of uracil and potentially other mutagenic base lesions in ssDNA at the replication fork, is orchestrated by RPA. The UNG:RPA2-WH interaction may also play a role in adaptive immunity by promoting efficient excision of AID-induced uracils in transcribed immunoglobulin loci.<br />Graphical Abstract Graphical AbstractThe WH-domain of RPA facilitates efficient UNG-mediated excision from RPA-coated ssDNA and may orchestrate error-free templated repair of the resultant AP-site.
- Subjects :
- DNA Replication
DNA repair
AcademicSubjects/SCI00010
DNA, Single-Stranded
Biology
Genome Integrity, Repair and Replication
DNA Glycosylases
03 medical and health sciences
chemistry.chemical_compound
0302 clinical medicine
Replication Protein A
Genetics
Humans
AP site
Uracil
Replication protein A
030304 developmental biology
0303 health sciences
Binding Sites
DNA replication
DNA Replication Fork
Recombinant Proteins
Cell biology
chemistry
DNA glycosylase
030217 neurology & neurosurgery
DNA
Protein Binding
Subjects
Details
- ISSN :
- 13624962
- Volume :
- 49
- Issue :
- 7
- Database :
- OpenAIRE
- Journal :
- Nucleic acids research
- Accession number :
- edsair.doi.dedup.....1300d8e4bf01fed7c211084f636c6fac