Premium
Repairing Interstrand DNA Crosslinks (ICL): Characterization of an ICL Incision/Lesion Bypass Polymerase Complex regulated by the Fanconi anemia pathway
Author(s) -
Jasti Vijay Prasad,
Sharma Shilpy,
Althaus Irene,
Weinstein Abby,
Ramani Shreyas,
Canman Christine
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.996.3
Subject(s) - dna repair , homologous recombination , fanconi anemia , biology , dna polymerase , dna damage , fancd2 , homology directed repair , microbiology and biotechnology , dna , polymerase , genome instability , genetics , nucleotide excision repair
The ‘REVersionless’ genes, REV1, REV3, and REV7, were discovered as being necessary for both spontaneous and DNA damage‐induced mutagenesis in yeast. REV3 is the catalytic subunit of DNA polymerase Zeta (ζ) and together with its accessory subunit REV7 extends nucleotides inserted opposite multiple types of DNA lesions. REV1 is a deoxycytidyl transferase and performs a scaffolding function in orchestrating the switch between insertion TLS polymerases directly opposite a DNA adduct and Polζ for the extension step. REV1 and Polζ are also involved in ICL repair and homologous recombination (HR) repair of DNA double stranded breaks (DSB). The phenotypes of cells deficient in expression of REV1, REV3, or REV7 are similar to cells derived from patients diagnosed with Fanconi Anemia (FA), a genetic disorder characterized by bone marrow failure, ICL hypersensitivity, and increased risk for cancer. Previous studies have demonstrated an epistatic relationship between REV1 or REV3 and genes encoding proteins comprising the FA core signaling complex in resistance to cisplatin. Additionally, REV1, Polζ, and the FANCD2/FANCI heterodimer have been shown individually to be involved in homologous recombination (HR) repair, which is crucial for resolution of DNA DSBs and ICL repair during S phase. We demonstrate that human REV1 and REV3 exhibit an epistatic relationship with FANCD2 and FANCI in cellular resistance and ICL repair following mitomycin C (MMC) treatment, as well as HR repair. MMC‐induced chromosomal anomalies are increased in REV1 or REV3‐depleted cells and FANCD2 depletion does not further exacerbate this phenotype. We further show that the FANCA core complex protein regulates MMC‐induced chromatin association of REV7 and by extension REV3 to sites of ICL repair. Co‐immunoprecipitation studies show that REV1, REV3 and REV7 interact with FANCD2 and FANCI independent of DNA damage or monoubiquitination of FANCD2 by the FA core complex. In addition, REV1, REV3, and REV7 co‐immunoprecipitate with the SLX4/FANCP scaffold protein, which regulates the unhooking step of an ICL DNA adduct by the ERCC1/XPF (FANCQ) endonuclease and HR repair of a DSB. We propose a model where REV1/Polζ‐dependent activities during ICL and HR repair are regulated by multiple FA proteins including FANCA, FANCD2 and SLX4 (FANCP). Together, these results suggest that REV1 and Polζ are part of a macromolecular complex involved in resistance to many anticancer agents and interactions within this complex may be viable targets for small molecule inhibitors to sensitize resistant tumors to chemotherapy. Support or Funding Information R01 CA133046