Oncogenetics plays a major role in the identification of gene defects leading to the genetic instability syndrome Fanconi anemia (FA). Patients suffering from this disease are characterized by chromosomal instability (chromatid breaks), especially seen upon treatment with DNA crosslinking agents (e.g. mitomycin C and cisplatin) to which FA cells are extremely sensitive. In addition, these patients are prone to develop cancer, in particular acute myeloid leukaemia (AML) and squamous cell carcinomas of the head and neck region.
The FA genes encode proteins that function in a DNA damage response network, which is probably involved in stabilizing the replication fork after replication has been stalled by roadblocks in the DNA (figure 1). The majority of FA proteins form a complex that is involved in the monoubiquitination of FANCD2 and FANCI. Several other proteins, including BRCA2 (alias FANCD1), function downstream or independent of this modification step. Defects in BRCA2 and its associated protein PALB2 (alias FANCN) lead to an extremely severe form of FA, with AML, medulloblastomas and Wilms tumours developing during childhood. Interestingly, the downstream part of the FA/BRCA network has also been associated with breast cancer.
Figure 1. Proteins involved in the FA/BRCA pathway. Defects in the coloured proteins have been found in FA patients. Proteins coloured in red are also involved in breast cancer.
Our research is focussed on the unravelling of the role of the FA/BRCA network in replication coupled DNA maintenance. To this aim we try to identify novel FA genes and breast cancer susceptibility genes and investigate their interrelationship. We have considerably contributed to the elucidation of the FA pathway by identifying 12 of the 15 currently known FA genes and 4 FA associated proteins in collaboration with many labs worldwide. Initially, we identified FA genes by complementation cloning. We then exploited the observation that the known FA proteins associated in a nuclear complex. Isolation of this complex led to the identification of 4 novel FA proteins: FANCL, FANCB, FANCM and FAAP100. Protein association studies also revealed the BRCA2-interacting protein PALB2 and the FANCM-associated proteins FAAP24, MHF1 and MHF2 as novel players in the pathway. Positional cloning was used to identify the genes encoding FANCI and FANCJ. A candidate gene approach led to the identification of SLX4 (alias FANCP) as a FA gene. Comprehensive mutation screening of unclassified FA patients indicates that there are at least four more FA genes that remain to be discovered. We use different methods to find these genes.
Currently, we also focus on the regulation of the FA pathway by post-translational modifications. To further study the FANCM protein, we have generated Fancm knockout mice, in collaboration with prof. H. Te Riele at the Netherlands Cancer Institute. This mouse model showed a role for FANCM in preventing tumorigenesis, which is now being explored in more detail. The role of the FA pathway in head and neck tumors and the consequence of its inactivation for the treatment of these tumors is also being investigated.
Bogliolo M * , Schuster B * , Stoepker C, Derkunt B, Su Y, Raams A, Trujillo JP, Minguillón J, Ramírez MJ, Pujol R, Casado JA, Baños R, Rio P, Knies K, Zúñiga S, Benítez J, Bueren JA, Jaspers NGJ, Schärer OD, de Winter JP, Schindler D + and Surrallés J + . Mutations in ERCC4, encoding the DNA repair endonuclease XPF, cause Fanconi anemia . Am J Hum Genet 92: 800-806, 2013
Ameziane N, Sie D, Dentro S, Ariyurek Y , Kerkhoven L, Joenje H, Dorsman JC, Ylstra B, Gille JJP, Sistermans EA and de Winter JP. Diagnosis of Fanconi anemia: Mutation analysis by next-generation sequencing. Anemia 2012
Schuster B*, Knies K*, Ameziane N, Rooimans MA, Bettecken T, de Winter JP and Schindler D. Genotyping of Fanconi Anemia Patients by Whole Exome Sequencing: Advantages and Challenges. PLOS ONE : 52648, 2012
Bakker ST, van de Vrugt HJ, Visser JA, Delzenne-Goette E, van der Wal A, Berns MAD, Rooimans MA, Oostra AB, Kramer P, Joenje H, Arwert F, van der Valk M, de Winter JP and te Riele HPJ. Fancf-deficient mice are prone to develop ovarian tumors. J. Pathol 226: 28-39, 2012
Stoepker C, Hain K, Schuster B, Hilhorst-Hofstee Y, Rooimans MA, Steltenpool J, Oostra AB, Eirich K, Korthof ET, Nieuwint AWM, Jaspers NGJ, Bettecken T, Joenje H, Schindler D+, Rouse J+, de Winter JP+. SLX4, a coördinator of structure-specific endonucleases, is mutated in a new Fanconi anemia subtype. Nat Genet 43: 138-141, 2011
Singh TR, Bakker ST, Agarwal S, Jansen M, Grassman E, Godthelp BC, Ali AM, Du C, Rooimans MA, Fan Q, Wahengbam K, Steltenpool J, Andreassen PR, Williams DA, Joenje H, de Winter JP+ and Meetei AR+. Mildly impaired FANCD2 monoubiquitination with hypersensitivity to camptothecin uniquely characterize Fanconi anemia complementation group M. Blood 114: 174-180, 2009
Bakker ST, van de Vrugt HJ, Rooimans MA, Oostra AB, Steltenpool J, Delzenne-Goette E, van der Wal A, van der Valk M, Joenje H, te Riele H+ and de Winter JP+. Fancm-deficient mice reveal unique features of Fanconi anemia complementation group M. Hum Mol Genet 18: 3484-3495, 2009
Van Zeeburg HJT, Snijders PJF, Wu T, Gluckman E, Soulier J, Surrales J, Castella M, Van der Wal JE, Wennerberg J, Califano J, Velleuer E, Dietrich R, Ebell W, Bloemena E, Joenje H, Leemans CR, Brakenhoff RH. Clinical and molecular characteristics of squamous cell carcinomas from Fanconi anemia patients. J Natl Cancer Inst 100: 1649-1653, 2008
Dorsman JC**, Levitus M**, Rockx D, Rooimans MA, Oostra AB, Haitjema A, Bakker ST, Steltenpool J, Schuler D, Mohan S, Schindler D, Arwert F, Pals G, Mathew CG, Waisfisz Q, de Winter JP and Joenje H. Identification of the Fanconi anemia complementation group I gene, FANCI. Cell. Oncol . 29:211-218, 2007
Xia B**, Dorsman JC**, Ameziane N, de Vries Y, Rooimans MA, Sheng Q, Pals G, Errami A, Gluckman E, Llera J, Wang W, Livingston DM+, Joenje H and de Winter JP+. Fanconi anemia is associated with a defect in the BRCA2 partner PALB2. Nat Genet 39: 159-161, 2007
Medhurst AL, Laghmani EH, Steltenpool J, Ferrer M, Fontaine C, de Groot J, Rooimans MA, Scheper RJ, Meetei AR, Wang W, Joenje H, and de Winter JP. Evidence for subcomplexes in the Fanconi anemia pathway. Blood 108: 2072-2080, 2006
Meetei AR, Medhurst AL, Ling C, Xue Y, Singh TR, Bier P, Steltenpool J, Stone S, Dokal I, Mathew CG, Hoatlin M, Joenje H, de Winter JP+ and Wang W+. A human ortholog of archaeal DNA repair protein Hef is defective in Fanconi anemia complementation group M. Nat Genet 37: 958-963, 2005
Levitus M**, Waisfisz Q**, Godthelp BC**, de Vries Y, Hussain S, Wiegant WW, Elghabzouri-Maghrani E, Steltenpool J, Rooimans M A, Pals G, Arwert F, Mathew CG, Zdzienicka MZ, Hiom K, de Winter JP and Joenje, H.. The DNA helicase BRIP1 is defective in Fanconi anemia complementation group J. Nat. Genet. 37: 934-935, 2005
Meetei AR**, Levitus M**, Xue Y, Medhurst AL, Zwaan M, Ling C, Rooimans MA, Bier P, Hoatlin M, Pals G, de Winter JP, Wang W+, Joenje H+. X-linked inheritance of Fanconi anemia complementation group B. Nat Gene t 36: 1219-1224, 2004
Meetei AR, de Winter JP, Medhurst AL, Wallisch M, Waisfisz Q, van de Vrugt HJ, Oostra AB, Yan Z, Ling C, Bishop CE, Hoatlin ME, Joenje H, and Wang W. A novel ubiquitin ligase is deficient in Fanconi anemia. Nat Genet 35: 165-70, 2003
Howlett NG, Taniguchi T, Olson S, Cox B, Waisfisz, Q , De Die-Smulders C, Persky N, Grompe M, Joenje H, Pals G, Ikeda H, Fox EA and D'Andrea AD. Biallelic inactivation of BRCA2 in Fanconi anemia . Science . 297: 606-609, 2002 .
de Winter JP, Léveillé F, van Berkel CGM, Rooimans MA, van der Weel L, Steltenpool J, Demuth I, Morgan NV, Alon N, Bosnoyan-Collins L, Lightfoot J, Komatsu K, Arwert F, Leegwater PA, Waisfisz Q, Pronk JC, Mathew CG, Digweed M, Buchwald M and Joenje H. Isolation of a cDNA representing the Fanconi anemia complementation group E gene. Am J Hum Genet 67: 1306-1308, 2000
de Winter JP, Rooimans MA, Van der Weel L, Van Berkel CGM, Alon N, Bosnoyan-Collins L, De Groot J, Zhi Y, Waisfisz Q, Pronk JC, Arwert F, Mathew CG, Scheper RJ, Hoatlin ME, Buchwald M, Joenje H: The Fanconi anaemia gene FANCF encodes a novel protein with homology to ROM. Nat Genet 24: 15-16, 2000
Waisfisz Q, Morgan NV, Savino M, de Winter JP, van Berkel CGM, Hoatlin ME, Ianzano L, Gibson RA, Arwert F, Savoia A, Mathew G, Pronk JC and Joenje H. Spontaneous functional correction of homozygous Fanconi anaemia alleles reveals novel mechanistic basis for reverse mosaicism. Nat Genet . 22: 379-383, 1999
de Winter JP**, Waisfisz Q**, Rooimans MA, van Berkel CGM, Bosnoyan-Collins L, Alon N, Carreau M, Bender O, Demuth I, Schindler D, Pronk JC, Arwert F, Hoehn H, Digweed M, Buchwald M and Joenje H. The Fanconi anaemia group G gene FANCG is identical with XRCC9. Nat Genet . 20: 281-283, 1998
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