Polymerase theta-helicase promotes end joining by stripping single-stranded DNA-binding proteins and bridging DNA ends.
Nucleic Acids Res
; 50(7): 3911-3921, 2022 04 22.
Article
in En
| MEDLINE
| ID: mdl-35357490
ABSTRACT
Homologous recombination-deficient cancers rely on DNA polymerase Theta (Polθ)-Mediated End Joining (TMEJ), an alternative double-strand break repair pathway. Polθ is the only vertebrate polymerase that encodes an N-terminal superfamily 2 (SF2) helicase domain, but the role of this helicase domain in TMEJ remains unclear. Using single-molecule imaging, we demonstrate that Polθ-helicase (Polθ-h) is a highly processive single-stranded DNA (ssDNA) motor protein that can efficiently strip Replication Protein A (RPA) from ssDNA. Polθ-h also has a limited capacity for disassembling RAD51 filaments but is not processive on double-stranded DNA. Polθ-h can bridge two non-complementary DNA strands in trans. PARylation of Polθ-h by PARP-1 resolves these DNA bridges. We conclude that Polθ-h removes RPA and RAD51 filaments and mediates bridging of DNA overhangs to aid in polymerization by the Polθ polymerase domain.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
DNA-Binding Proteins
/
DNA End-Joining Repair
Language:
En
Journal:
Nucleic Acids Res
Year:
2022
Document type:
Article
Affiliation country:
United States