A Genetic Screen Identifies FAN1, a Fanconi Anemia-Associated Nuclease Necessary for DNA Interstrand Crosslink Repair

Howard Hughes Medical Institute, Department of Genetics, Harvard Medical School, and Brigham and Women's Hospital, Boston, MA 02115, USA.
Molecular cell (Impact Factor: 14.46). 07/2010; 39(1):36-47. DOI: 10.1016/j.molcel.2010.06.023
Source: PubMed

ABSTRACT The Fanconi anemia (FA) pathway is responsible for interstrand crosslink repair. At the heart of this pathway is the FANCI-FAND2 (ID) complex, which, upon ubiquitination by the FA core complex, travels to sites of damage to coordinate repair that includes nucleolytic modification of the DNA surrounding the lesion and translesion synthesis. How the ID complex regulates these events is unknown. Here we describe a shRNA screen that led to the identification of two nucleases necessary for crosslink repair, FAN1 (KIAA1018) and EXDL2. FAN1 colocalizes at sites of DNA damage with the ID complex in a manner dependent on FAN1's ubiquitin-binding domain (UBZ), the ID complex, and monoubiquitination of FANCD2. FAN1 possesses intrinsic 5'-3' exonuclease activity and endonuclease activity that cleaves nicked and branched structures. We propose that FAN1 is a repair nuclease that is recruited to sites of crosslink damage in part through binding the ubiquitinated ID complex through its UBZ domain.

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    ABSTRACT: Dear Editor,DNA interstrand crosslinks (ICLs) are toxic to cells because they covalently link the two strands in the duplex. ICLs can be induced by crosslinking agents and by cell endogenous metabolites, and physically prevent transcription and replication in both directions (MacKay et al., 2010). This type of DNA damage must be properly repaired to maintain genomic and cellular integrity, and this repair is primarily accomplished by the Fanconi anemia pathway (FA pathway) (Moldovan and D’Andrea, 2009). FA is an inherited recessive developmental and cancer predisposition syndrome that can be caused by defects in any of 16 FANC proteins (Chaudhury et al., 2014). The removal of ICLs depends on numerous components involved in multiple DNA repair pathways such as nucleotide excision repair (NER), mismatch repair (MMR), translesion synthesis (TLS) and homologous recombination (HR), and several models have been previously proposed (Fu et al., 2011; Huang et al., 2013; Kratz et al., 2010). Am ...
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