FANC pathway promotes UV-induced stalled replication forks recovery by acting both upstream and downstream Polη and Rev1.
To cope with ultraviolet C (UVC)-stalled replication forks and restart DNA synthesis, cells either undergo DNA translesion synthesis (TLS) by specialised DNA polymerases or tolerate the lesions using homologous recombination (HR)-based mechanisms. To gain insight into how cells manage UVC-induced stalled replication forks, we analysed the molecular crosstalk between the TLS DNA polymerases Polη and Rev1, the double-strand break repair (DSB)-associated protein MDC1 and the FANC pathway. We describe three novel functional interactions that occur in response to UVC-induced DNA lesions. First, Polη and Rev1, whose optimal expression and/or relocalisation depend on the FANC core complex, act upstream of FANCD2 and are required for the proper relocalisation of monoubiquitinylated FANCD2 (Ub-FANCD2) to subnuclear foci. Second, during S-phase, Ub-FANCD2 and MDC1 relocalise to UVC-damaged nuclear areas or foci simultaneously but independently of each other. Third, Ub-FANCD2 and MDC1 are independently required for optimal BRCA1 relocalisation. While RPA32 phosphorylation (p-RPA32) and RPA foci formation were reduced in parallel with increasing levels of H2AX phosphorylation and MDC1 foci in UVC-irradiated FANC pathway-depleted cells, MDC1 depletion was associated with increased UVC-induced Ub-FANCD2 and FANCD2 foci as well as p-RPA32 levels and p-RPA32 foci. On the basis of the previous observations, we propose that the FANC pathway participates in the rescue of UVC-stalled replication forks in association with TLS by maintaining the integrity of ssDNA regions and by preserving genome stability and preventing the formation of DSBs, the resolution of which would require the intervention of MDC1.
Université Paris Sud, UMR8200, Equipe Labellisée Ligue Contre Cancer, Institut de Cancérologie Gustave-Roussy, Villejuif, France.
Emilie
E
Renaud
Filippo
F
Rosselli
D048868:Adaptor Proteins, Signal Transducing; D019313:BRCA1 Protein / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins; D045744:Cell Line, Tumor; D004261:DNA Replication / Q000528:radiation effects*; D004277:DNA, Single-Stranded; D004259:DNA-Directed DNA Polymerase / Q000235:genetics* / Q000378:metabolism; D052236:Fanconi Anemia Complementation Group D2 Protein / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000528:radiation effects*; D006657:Histones / Q000235:genetics / Q000378:metabolism; D006801:Humans; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D009713:Nucleotidyltransferases / Q000235:genetics* / Q000378:metabolism; D010766:Phosphorylation / Q000528:radiation effects; D021381:Protein Transport / Q000528:radiation effects; D051716:Replication Protein A / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000528:radiation effects; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D054875:Ubiquitination / Q000528:radiation effects; D014466:Ultraviolet Rays; D000099270:Y-Family DNA Polymerases
D048868:Adaptor Proteins, Signal Transducing; D019313:BRCA1 Protein; D018797:Cell Cycle Proteins; D004277:DNA, Single-Stranded; D004259:DNA-Directed DNA Polymerase; D052236:Fanconi Anemia Complementation Group D2 Protein; D006657:Histones; D009687:Nuclear Proteins; D009713:Nucleotidyltransferases; D051716:Replication Protein A; D015534:Trans-Activators; C492913:BRCA1 protein, human; C499905:FANCD2 protein, human; C468783:H2AX protein, human; C413163:MDC1 protein, human; C429004:REV1 protein, human; D000099270:Y-Family DNA Polymerases; C516794:RPA2 protein, human; C112338:Rad30 protein