Human Rev1 relies on insert-2 to promote selective binding and accurate replication of stabilized G-quadruplex motifs.
Nucleic Acids Res
; 49(4): 2065-2084, 2021 02 26.
Article
in En
| MEDLINE
| ID: mdl-33555350
ABSTRACT
We previously reported that human Rev1 (hRev1) bound to a parallel-stranded G-quadruplex (G4) from the c-MYC promoter with high affinity. We have extended those results to include other G4 motifs, finding that hRev1 exhibited stronger affinity for parallel-stranded G4 than either anti-parallel or hybrid folds. Amino acids in the αE helix of insert-2 were identified as being important for G4 binding. Mutating E466 and Y470 to alanine selectively perturbed G4 binding affinity. The E466K mutant restored wild-type G4 binding properties. Using a forward mutagenesis assay, we discovered that loss of hRev1 increased G4 mutation frequency >200-fold compared to the control sequence. Base substitutions and deletions occurred around and within the G4 motif. Pyridostatin (PDS) exacerbated this effect, as the mutation frequency increased >700-fold over control and deletions upstream of the G4 site more than doubled. Mutagenic replication of G4 DNA (±PDS) was partially rescued by wild-type and E466K hRev1. The E466A or Y470A mutants failed to suppress the PDS-induced increase in G4 mutation frequency. These findings have implications for the role of insert-2, a motif conserved in vertebrates but not yeast or plants, in Rev1-mediated suppression of mutagenesis during G4 replication.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
DNA
/
DNA Replication
/
G-Quadruplexes
/
Nucleotidyltransferases
Type of study:
Prognostic_studies
Limits:
Humans
Language:
En
Journal:
Nucleic Acids Res
Year:
2021
Document type:
Article