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1.
J Med Genet ; 57(4): 258-268, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31586946

RESUMO

PURPOSE: Patients with Fanconi anaemia (FA), a rare DNA repair genetic disease, exhibit chromosome fragility, bone marrow failure, malformations and cancer susceptibility. FA molecular diagnosis is challenging since FA is caused by point mutations and large deletions in 22 genes following three heritability patterns. To optimise FA patients' characterisation, we developed a simplified but effective methodology based on whole exome sequencing (WES) and functional studies. METHODS: 68 patients with FA were analysed by commercial WES services. Copy number variations were evaluated by sequencing data analysis with RStudio. To test FANCA missense variants, wt FANCA cDNA was cloned and variants were introduced by site-directed mutagenesis. Vectors were then tested for their ability to complement DNA repair defects of a FANCA-KO human cell line generated by TALEN technologies. RESULTS: We identified 93.3% of mutated alleles including large deletions. We determined the pathogenicity of three FANCA missense variants and demonstrated that two FANCA variants reported in mutations databases as 'affecting functions' are SNPs. Deep analysis of sequencing data revealed patients' true mutations, highlighting the importance of functional analysis. In one patient, no pathogenic variant could be identified in any of the 22 known FA genes, and in seven patients, only one deleterious variant could be identified (three patients each with FANCA and FANCD2 and one patient with FANCE mutations) CONCLUSION: WES and proper bioinformatics analysis are sufficient to effectively characterise patients with FA regardless of the rarity of their complementation group, type of mutations, mosaic condition and DNA source.

2.
NPJ Breast Cancer ; 5: 38, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31700994

RESUMO

Breast cancer is a common disease partially caused by genetic risk factors. Germline pathogenic variants in DNA repair genes BRCA1, BRCA2, PALB2, ATM, and CHEK2 are associated with breast cancer risk. FANCM, which encodes for a DNA translocase, has been proposed as a breast cancer predisposition gene, with greater effects for the ER-negative and triple-negative breast cancer (TNBC) subtypes. We tested the three recurrent protein-truncating variants FANCM:p.Arg658*, p.Gln1701*, and p.Arg1931* for association with breast cancer risk in 67,112 cases, 53,766 controls, and 26,662 carriers of pathogenic variants of BRCA1 or BRCA2. These three variants were also studied functionally by measuring survival and chromosome fragility in FANCM -/- patient-derived immortalized fibroblasts treated with diepoxybutane or olaparib. We observed that FANCM:p.Arg658* was associated with increased risk of ER-negative disease and TNBC (OR = 2.44, P = 0.034 and OR = 3.79; P = 0.009, respectively). In a country-restricted analysis, we confirmed the associations detected for FANCM:p.Arg658* and found that also FANCM:p.Arg1931* was associated with ER-negative breast cancer risk (OR = 1.96; P = 0.006). The functional results indicated that all three variants were deleterious affecting cell survival and chromosome stability with FANCM:p.Arg658* causing more severe phenotypes. In conclusion, we confirmed that the two rare FANCM deleterious variants p.Arg658* and p.Arg1931* are risk factors for ER-negative and TNBC subtypes. Overall our data suggest that the effect of truncating variants on breast cancer risk may depend on their position in the gene. Cell sensitivity to olaparib exposure, identifies a possible therapeutic option to treat FANCM-associated tumors.

3.
Nat Med ; 25(9): 1396-1401, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31501599

RESUMO

Fanconi anemia (FA) is a DNA repair syndrome generated by mutations in any of the 22 FA genes discovered to date1,2. Mutations in FANCA account for more than 60% of FA cases worldwide3,4. Clinically, FA is associated with congenital abnormalities and cancer predisposition. However, bone marrow failure is the primary pathological feature of FA that becomes evident in 70-80% of patients with FA during the first decade of life5,6. In this clinical study (ClinicalTrials.gov, NCT03157804 ; European Clinical Trials Database, 2011-006100-12), we demonstrate that lentiviral-mediated hematopoietic gene therapy reproducibly confers engraftment and proliferation advantages of gene-corrected hematopoietic stem cells (HSCs) in non-conditioned patients with FA subtype A. Insertion-site analyses revealed the multipotent nature of corrected HSCs and showed that the repopulation advantage of these cells was not due to genotoxic integrations of the therapeutic provirus. Phenotypic correction of blood and bone marrow cells was shown by the acquired resistance of hematopoietic progenitors and T lymphocytes to DNA cross-linking agents. Additionally, an arrest of bone marrow failure progression was observed in patients with the highest levels of gene marking. The progressive engraftment of corrected HSCs in non-conditioned patients with FA supports that gene therapy should constitute an innovative low-toxicity therapeutic option for this life-threatening disorder.


Assuntos
Proteína do Grupo de Complementação A da Anemia de Fanconi/genética , Anemia de Fanconi/terapia , Terapia Genética , Transplante de Células-Tronco Hematopoéticas , Adolescente , Adulto , Células da Medula Óssea/citologia , Criança , Pré-Escolar , Anemia de Fanconi/genética , Anemia de Fanconi/fisiopatologia , Feminino , Vetores Genéticos/genética , Células-Tronco Hematopoéticas/metabolismo , Humanos , Lactente , Lentivirus/genética , Masculino , Mutação/genética , Espanha/epidemiologia , Reparo Gênico Alvo-Dirigido , Transdução Genética , Adulto Jovem
4.
Cell Stem Cell ; 25(5): 607-621.e7, 2019 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-31543367

RESUMO

Non-homologous end-joining (NHEJ) is the preferred mechanism used by hematopoietic stem cells (HSCs) to repair double-stranded DNA breaks and is particularly increased in cells deficient in the Fanconi anemia (FA) pathway. Here, we show feasible correction of compromised functional phenotypes in hematopoietic cells from multiple FA complementation groups, including FA-A, FA-C, FA-D1, and FA-D2. NHEJ-mediated repair of targeted CRISPR-Cas9-induced DNA breaks generated compensatory insertions and deletions that restore the coding frame of the mutated gene. NHEJ-mediated editing efficacy was initially verified in FA lymphoblastic cell lines and then in primary FA patient-derived CD34+ cells, which showed marked proliferative advantage and phenotypic correction both in vitro and after transplantation. Importantly, and in contrast to homologous directed repair, NHEJ efficiently targeted primitive human HSCs, indicating that NHEJ editing approaches may constitute a sound alternative for editing self-renewing human HSCs and consequently for treatment of FA and other monogenic diseases affecting the hematopoietic system.


Assuntos
Sistemas CRISPR-Cas/genética , Reparo do DNA por Junção de Extremidades/genética , Proteína do Grupo de Complementação A da Anemia de Fanconi/genética , Anemia de Fanconi/terapia , Edição de Genes/métodos , Terapia Genética/métodos , Transplante de Células-Tronco Hematopoéticas , Alelos , Animais , Antígenos CD34/metabolismo , Linhagem Celular , Proliferação de Células/genética , Quebras de DNA de Cadeia Dupla , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Proteína do Grupo de Complementação A da Anemia de Fanconi/metabolismo , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Transplante de Células-Tronco Hematopoéticas/métodos , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Mutação INDEL , Camundongos , Camundongos Endogâmicos NOD , Camundongos Nus
5.
Genes (Basel) ; 10(1)2019 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-30658521

RESUMO

XPF endonuclease is one of the most important DNA repair proteins. Encoded by XPF/ERCC4, XPF provides the enzymatic activity of XPF-ERCC1 heterodimer, an endonuclease that incises at the 5' side of various DNA lesions. XPF is essential for nucleotide excision repair (NER) and interstrand crosslink repair (ICLR). XPF/ERCC4 mutations are associated with several human diseases: Xeroderma Pigmentosum (XP), Segmental Progeria (XFE), Fanconi Anemia (FA), Cockayne Syndrome (CS), and XP/CS combined disease (XPCSCD). Most affected individuals are compound heterozygotes for XPF/ERCC4 mutations complicating the identification of genotype/phenotype correlations. We report a detailed overview of NER and ICLR functional studies in human XPF-KO (knock-out) isogenic cells expressing six disease-specific pathogenic XPF amino acid substitution mutations. Ultraviolet (UV) sensitivity and unscheduled DNA synthesis (UDS) assays provide the most reliable information to discern mutations associated with ICLR impairment from mutations related to NER deficiency, whereas recovery of RNA synthesis (RRS) assays results hint to a possible role of XPF in resolving R-loops. Our functional studies demonstrate that a defined cellular phenotype cannot be easily correlated to each XPF mutation. Substituted positions along XPF sequences are not predictive of cellular phenotype nor reflect a particular disease. Therefore, in addition to mutation type, allelic interactions, protein stability and intracellular distribution of mutant proteins may also contribute to alter DNA repair pathways balance leading to clinically distinct disorders.


Assuntos
Distúrbios no Reparo do DNA/genética , Proteínas de Ligação a DNA/genética , Mutação de Sentido Incorreto , Fenótipo , Reparo do DNA , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Células HEK293 , Humanos , Estabilidade Proteica , Tolerância a Radiação
6.
Genet Med ; 21(1): 189-194, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-29904161

RESUMO

PURPOSE: In about 10% of patients affected by Fanconi anemia (FA) the diagnosis is delayed until adulthood, and the presenting symptom in these "occult" FA cases is often a solid cancer and cancer treatment-related toxicity. Highly predictive clinical parameter(s) for diagnosing such an adult-onset cases are missing. METHODS: (1) Exome sequencing (ES), (2) Sanger sequencing of FANCA, (3) diepoxybutane (DEB)-induced chromosome breakage test. RESULTS: ES identified a pathogenic homozygous FANCA variant in a patient affected by Sertoli cell-only syndrome (SCOS) and in his azoospermic brother. Although they had no overt anemia, chromosomal breakage test revealed a reverse somatic mosaicism in the former and a typical FA picture in the latter. In 27 selected SCOS cases, 1 additional patient showing compound heterozygous pathogenic FANCA variants was identified with positive chromosomal breakage test. CONCLUSION: We report an extraordinarily high frequency of FA in a specific subgroup of azoospermic patients (7.1%). The screening for FANCA pathogenic variants in such patients has the potential to identify undiagnosed FA before the appearance of other severe clinical manifestations of the disease. The definition of this high-risk group for "occult" FA, based on specific testis phenotype with mild/borderline hematological alterations, is of unforeseen clinical relevance.


Assuntos
Azoospermia/genética , Proteína do Grupo de Complementação A da Anemia de Fanconi/genética , Anemia de Fanconi/genética , Síndrome de Células de Sertoli/genética , Adulto , Idade de Início , Azoospermia/sangue , Azoospermia/complicações , Azoospermia/patologia , Quebra Cromossômica , Exoma/genética , Anemia de Fanconi/sangue , Anemia de Fanconi/diagnóstico , Anemia de Fanconi/patologia , Feminino , Regulação da Expressão Gênica/genética , Humanos , Masculino , Mutação , Linhagem , Fenótipo , Síndrome de Células de Sertoli/sangue , Síndrome de Células de Sertoli/complicações , Síndrome de Células de Sertoli/patologia , Testículo/metabolismo , Testículo/patologia , Sequenciamento Completo do Exoma
8.
Am J Hum Genet ; 103(2): 221-231, 2018 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-30057030

RESUMO

Bloom syndrome, caused by biallelic mutations in BLM, is characterized by prenatal-onset growth deficiency, short stature, an erythematous photosensitive malar rash, and increased cancer predisposition. Diagnostically, a hallmark feature is the presence of increased sister chromatid exchanges (SCEs) on cytogenetic testing. Here, we describe biallelic mutations in TOP3A in ten individuals with prenatal-onset growth restriction and microcephaly. TOP3A encodes topoisomerase III alpha (TopIIIα), which binds to BLM as part of the BTRR complex, and promotes dissolution of double Holliday junctions arising during homologous recombination. We also identify a homozygous truncating variant in RMI1, which encodes another component of the BTRR complex, in two individuals with microcephalic dwarfism. The TOP3A mutations substantially reduce cellular levels of TopIIIα, and consequently subjects' cells demonstrate elevated rates of SCE. Unresolved DNA recombination and/or replication intermediates persist into mitosis, leading to chromosome segregation defects and genome instability that most likely explain the growth restriction seen in these subjects and in Bloom syndrome. Clinical features of mitochondrial dysfunction are evident in several individuals with biallelic TOP3A mutations, consistent with the recently reported additional function of TopIIIα in mitochondrial DNA decatenation. In summary, our findings establish TOP3A mutations as an additional cause of prenatal-onset short stature with increased cytogenetic SCEs and implicate the decatenation activity of the BTRR complex in their pathogenesis.

9.
Nat Commun ; 9(1): 967, 2018 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-29511213

RESUMO

BRCA1 is a tumor suppressor that regulates DNA repair by homologous recombination. Germline mutations in BRCA1 are associated with increased risk of breast and ovarian cancer and BRCA1 deficient tumors are exquisitely sensitive to poly (ADP-ribose) polymerase (PARP) inhibitors. Therefore, uncovering additional components of this DNA repair pathway is of extreme importance for further understanding cancer development and therapeutic vulnerabilities. Here, we identify EDC4, a known component of processing-bodies and regulator of mRNA decapping, as a member of the BRCA1-BRIP1-TOPBP1 complex. EDC4 plays a key role in homologous recombination by stimulating end resection at double-strand breaks. EDC4 deficiency leads to genome instability and hypersensitivity to DNA interstrand cross-linking drugs and PARP inhibitors. Lack-of-function mutations in EDC4 were detected in BRCA1/2-mutation-negative breast cancer cases, suggesting a role in breast cancer susceptibility. Collectively, this study recognizes EDC4 with a dual role in decapping and DNA repair whose inactivation phenocopies BRCA1 deficiency.


Assuntos
Proteína BRCA1/metabolismo , Neoplasias da Mama/metabolismo , Reparo do DNA , Proteínas/metabolismo , Proteína BRCA1/genética , Neoplasias da Mama/genética , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Feminino , Recombinação Homóloga , Humanos , Mutação , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Poli(ADP-Ribose) Polimerase-1/genética , Poli(ADP-Ribose) Polimerase-1/metabolismo , Ligação Proteica , Proteínas/genética , Capuzes de RNA/genética , Capuzes de RNA/metabolismo
10.
Genet Med ; 20(4): 458-463, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-28837157

RESUMO

PurposeMutations in genes involved in Fanconi anemia (FA)/BRCA DNA repair pathway cause cancer susceptibility diseases including familial breast cancer and Fanconi anemia (FA). A single FA patient with biallelic FANCM mutations was reported in 2005 but concurrent FANCA pathogenic mutations precluded assignment of FANCM as an FA gene. Here we report three individuals with biallelic FANCM truncating mutations who developed early-onset cancer and toxicity to chemotherapy but did not present congenital malformations or any hematological phenotype suggestive of FA.MethodsChromosomal breakages, interstrand crosslink sensitivity, and FANCD2 monoubiquitination were assessed in primary fibroblasts. Mutation analysis was achieved through Sanger sequencing. Genetic complementation of patient-derived cells was performed by lentiviral mediated transduction of wild-type FANCM complementary DNA followed by functional studies.ResultsPatient-derived cells exhibited chromosomal fragility, hypersensitivity to interstrand crosslinks, and impaired FANCD2 monoubiquitination. We identified two homozygous mutations (c.2586_2589del4; p.Lys863Ilefs*12 and c.1506_1507insTA; p.Ile503*) in FANCM as the cause of the cellular phenotype. Patient-derived cells were genetically complemented upon wild-type FANCM complementary DNA expression.ConclusionLoss-of-function mutations in FANCM cause a cancer predisposition syndrome clinically distinct from bona fide FA. Care should be taken with chemotherapy and radiation treatments in these patients due to expected acute toxicity.


Assuntos
Alelos , DNA Helicases/genética , Anemia de Fanconi/genética , Predisposição Genética para Doença , Neoplasias/diagnóstico , Neoplasias/genética , Deleção de Sequência , Adolescente , Linhagem Celular , Fragilidade Cromossômica/efeitos dos fármacos , DNA Helicases/metabolismo , Feminino , Estudos de Associação Genética , Teste de Complementação Genética , Homozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , Fenótipo
11.
Genet Med ; 20(4): 452-457, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-28837162

RESUMO

PurposeMonoallelic germ-line mutations in the BRCA1/FANCS, BRCA2/FANCD1 and PALB2/FANCN genes confer high risk of breast cancer. Biallelic mutations in these genes cause Fanconi anemia (FA), characterized by malformations, bone marrow failure, chromosome fragility, and cancer predisposition (BRCA2/FANCD1 and PALB2/FANCN), or an FA-like disease presenting a phenotype similar to FA but without bone marrow failure (BRCA1/FANCS). FANCM monoallelic mutations have been reported as moderate risk factors for breast cancer, but there are no reports of any clinical phenotype observed in carriers of biallelic mutations.MethodsBreast cancer probands were subjected to mutation analysis by sequencing gene panels or testing DNA damage response genes.ResultsFive cases homozygous for FANCM loss-of-function mutations were identified. They show a heterogeneous phenotype including cancer predisposition, toxicity to chemotherapy, early menopause, and possibly chromosome fragility. Phenotype severity might correlate with mutation position in the gene.ConclusionOur data indicate that biallelic FANCM mutations do not cause classical FA, providing proof that FANCM is not a canonical FA gene. Moreover, our observations support previous findings suggesting that FANCM is a breast cancer-predisposing gene. Mutation testing of FANCM might be considered for individuals with the above-described clinical features.


Assuntos
Alelos , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/genética , Fragilidade Cromossômica , DNA Helicases/genética , Anemia de Fanconi/diagnóstico , Anemia de Fanconi/genética , Predisposição Genética para Doença , Mutação , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Consanguinidade , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Estudos de Associação Genética , Genótipo , Mutação em Linhagem Germinativa , Humanos , Masculino , Linhagem , Fenótipo , Medição de Risco , Fatores de Risco
12.
Artigo em Inglês | MEDLINE | ID: mdl-26520367

RESUMO

Fanconi anemia (FA) is a rare, clinically heterogeneous autosomal recessive or X-linked genetic disease characterized by chromosome fragility, congenital malformations and cancer susceptibility. FA patients are usually radiosensitive when exposed to radiotherapy but the role of the FA in response to ionizing radiation (IR) is controversial. Here we have investigated IR-induced activation of the FA pathway by systematically analyzing monoubiquitination of the central protein FANCD2 and subsequent recruitment to stalled replication forks in primary fibroblasts. We developed an immunolabelling method to simultaneously visualize IR-induced FANCD2 and γH2AX foci in S-phase. We observed FANCD2 foci formation in a subset of IR-induced γH2AX foci in S-phase cells. This was observed at doses of IR ranging from 0.1 to 5.0Gy in a dose dependent non-threshold fashion. Our results indicate that minimum doses of IR can produce replication fork stalling and FA pathway activation during S-phase in primary cells.


Assuntos
Proteína do Grupo de Complementação D2 da Anemia de Fanconi/metabolismo , Fibroblastos/efeitos da radiação , Histonas/metabolismo , Fase S/efeitos da radiação , Transdução de Sinais/efeitos da radiação , Linhagem Celular , Pré-Escolar , Relação Dose-Resposta à Radiação , Fibroblastos/metabolismo , Humanos , Fosforilação , Radiação Ionizante , Ubiquitinação
13.
Curr Opin Genet Dev ; 33: 32-40, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26254775

RESUMO

Fanconi anemia (FA) is characterized by bone marrow failure, malformations, and chromosome fragility. We review the recent discovery of FA genes and efforts to develop genetic therapies for FA in the last five years. Because current data exclude FANCM as an FA gene, 15 genes remain bona fide FA genes and three (FANCO, FANCR and FANCS) cause an FA like syndrome. Monoallelic mutations in 6 FA associated genes (FANCD1, FANCJ, FANCM, FANCN, FANCO and FANCS) predispose to breast and ovarian cancer. The products of all these genes are involved in the repair of stalled DNA replication forks by unhooking DNA interstrand cross-links and promoting homologous recombination. The genetic characterization of patients with FA is essential for developing therapies, including hematopoietic stem cell transplantation from a savior sibling donor after embryo selection, gene therapy, or genome editing using genetic recombination or engineered nucleases. Newly acquired knowledge about FA promises to provide therapeutic strategies in the near future.


Assuntos
DNA Helicases/genética , Anemia de Fanconi/genética , Anemia de Fanconi/terapia , Terapia Genética , Medula Óssea/metabolismo , Medula Óssea/patologia , Fragilidade Cromossômica/genética , Anemia de Fanconi/patologia , Transplante de Células-Tronco Hematopoéticas , Humanos , Mutação , Edição de RNA/genética
14.
Hum Mol Genet ; 24(18): 5345-55, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-26130695

RESUMO

Numerous genetic factors that influence breast cancer risk are known. However, approximately two-thirds of the overall familial risk remain unexplained. To determine whether some of the missing heritability is due to rare variants conferring high to moderate risk, we tested for an association between the c.5791C>T nonsense mutation (p.Arg1931*; rs144567652) in exon 22 of FANCM gene and breast cancer. An analysis of genotyping data from 8635 familial breast cancer cases and 6625 controls from different countries yielded an association between the c.5791C>T mutation and breast cancer risk [odds ratio (OR) = 3.93 (95% confidence interval (CI) = 1.28-12.11; P = 0.017)]. Moreover, we performed two meta-analyses of studies from countries with carriers in both cases and controls and of all available data. These analyses showed breast cancer associations with OR = 3.67 (95% CI = 1.04-12.87; P = 0.043) and OR = 3.33 (95% CI = 1.09-13.62; P = 0.032), respectively. Based on information theory-based prediction, we established that the mutation caused an out-of-frame deletion of exon 22, due to the creation of a binding site for the pre-mRNA processing protein hnRNP A1. Furthermore, genetic complementation analyses showed that the mutation influenced the DNA repair activity of the FANCM protein. In summary, we provide evidence for the first time showing that the common p.Arg1931* loss-of-function variant in FANCM is a risk factor for familial breast cancer.


Assuntos
Processamento Alternativo , Códon sem Sentido , DNA Helicases/genética , Reparo do DNA , Éxons , Adulto , Idade de Início , Alelos , Sítios de Ligação , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/genética , Estudos de Casos e Controles , DNA Helicases/metabolismo , Análise Mutacional de DNA , Feminino , Expressão Gênica , Frequência do Gene , Estudos de Associação Genética , Predisposição Genética para Doença , Genótipo , Ribonucleoproteína Nuclear Heterogênea A1 , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/metabolismo , Humanos , Metanálise como Assunto , Pessoa de Meia-Idade , Motivos de Nucleotídeos , Matrizes de Pontuação de Posição Específica , Ligação Proteica , Fatores de Risco , Adulto Jovem
15.
Hum Mutat ; 34(12): 1615-8, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24027083

RESUMO

Recently, it has been reported that biallelic mutations in the ERCC4 (FANCQ) gene cause Fanconi anemia (FA) subtype FA-Q. To investigate the possible role of ERCC4 in breast and ovarian cancer susceptibility, as occurs with other FA genes, we screened the 11 coding exons and exon-intron boundaries of ERCC4 in 1573 index cases from high-risk Spanish familial breast and ovarian cancer pedigrees that had been tested negative for BRCA1 and BRCA2 mutations and 854 controls. The frequency of ERCC4 mutation carriers does not differ between cases and controls, suggesting that ERCC4 is not a cancer susceptibility gene. Interestingly, the prevalence of ERCC4 mutation carriers (one in 288) is similar to that reported for FANCA, whereas there are approximately 100-fold more FA-A than FA-Q patients, indicating that most biallelic combinations of ERCC4 mutations are embryo lethal. Finally, we identified additional bone-fide FA ERCC4 mutations specifically disrupting interstrand cross-link repair.


Assuntos
Alelos , Neoplasias da Mama/congênito , Proteínas de Ligação a DNA/genética , Predisposição Genética para Doença , Variação Genética , Neoplasias Ovarianas/genética , Substituição de Aminoácidos , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Estudos de Casos e Controles , Proteínas de Ligação a DNA/metabolismo , Éxons , Feminino , Síndrome Hereditária de Câncer de Mama e Ovário , Heterozigoto , Humanos , Mutação , Neoplasias Ovarianas/metabolismo , Fenótipo , Espanha
16.
Am J Hum Genet ; 92(5): 800-6, 2013 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-23623386

RESUMO

Fanconi anemia (FA) is a rare genomic instability disorder characterized by progressive bone marrow failure and predisposition to cancer. FA-associated gene products are involved in the repair of DNA interstrand crosslinks (ICLs). Fifteen FA-associated genes have been identified, but the genetic basis in some individuals still remains unresolved. Here, we used whole-exome and Sanger sequencing on DNA of unclassified FA individuals and discovered biallelic germline mutations in ERCC4 (XPF), a structure-specific nuclease-encoding gene previously connected to xeroderma pigmentosum and segmental XFE progeroid syndrome. Genetic reversion and wild-type ERCC4 cDNA complemented the phenotype of the FA cell lines, providing genetic evidence that mutations in ERCC4 cause this FA subtype. Further biochemical and functional analysis demonstrated that the identified FA-causing ERCC4 mutations strongly disrupt the function of XPF in DNA ICL repair without severely compromising nucleotide excision repair. Our data show that depending on the type of ERCC4 mutation and the resulting balance between both DNA repair activities, individuals present with one of the three clinically distinct disorders, highlighting the multifunctional nature of the XPF endonuclease in genome stability and human disease.


Assuntos
Proteínas de Ligação a DNA/genética , Desoxirribonucleases/genética , Anemia de Fanconi/genética , Predisposição Genética para Doença/genética , Fenótipo , Apoptose/genética , Apoptose/efeitos da radiação , Sequência de Bases , Exoma/genética , Anemia de Fanconi/patologia , Mutação em Linhagem Germinativa/genética , Humanos , Immunoblotting , Imunoprecipitação , Dados de Sequência Molecular , Análise de Sequência de DNA , Raios Ultravioleta
17.
Blood ; 120(1): 86-9, 2012 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-22611161

RESUMO

Fanconi anemia (FA) is a rare bone marrow failure disorder with defective DNA interstrand crosslink repair. Still, there are FA patients without mutations in any of the 15 genes individually underlying the disease. A candidate protein for those patients, FA nuclease 1 (FAN1), whose gene is located at chromosome 15q13.3, is recruited to stalled replication forks by binding to monoubiquitinated FANCD2 and is required for interstrand crosslink repair, suggesting that mutation of FAN1 may cause FA. Here we studied clinical, cellular, and genetic features in 4 patients carrying a homozygous 15q13.3 micro-deletion, including FAN1 and 6 additional genes. Biallelic deletion of the entire FAN1 gene was confirmed by failure of 3'- and 5'-PCR amplification. Western blot analysis failed to show FAN1 protein in the patients' cell lines. Chromosome fragility was normal in all 4 FAN1-deficient patients, although their cells showed mild sensitivity to mitomycin C in terms of cell survival and G(2) phase arrest, dissimilar in degree to FA cells. Clinically, there were no symptoms pointing the way to FA. Our results suggest that FAN1 has a minor role in interstrand crosslink repair compared with true FA genes and exclude FAN1 as a novel FA gene.


Assuntos
Reparo do DNA/fisiologia , Exodesoxirribonucleases/genética , Exodesoxirribonucleases/fisiologia , Anemia de Fanconi/genética , Anemia de Fanconi/fisiopatologia , Sobrevivência Celular/fisiologia , Células Cultivadas , Criança , Pré-Escolar , Cromossomos Humanos Par 15 , Replicação do DNA/fisiologia , Endodesoxirribonucleases , Anemia de Fanconi/patologia , Deleção de Genes , Homozigoto , Humanos , Lactente , Enzimas Multifuncionais
18.
Breast Cancer Res ; 13(2): R40, 2011 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-21466675

RESUMO

INTRODUCTION: Proteins encoded by Fanconi anemia (FA) and/or breast cancer (BrCa) susceptibility genes cooperate in a common DNA damage repair signaling pathway. To gain deeper insight into this pathway and its influence on cancer risk, we searched for novel components through protein physical interaction screens. METHODS: Protein physical interactions were screened using the yeast two-hybrid system. Co-affinity purifications and endogenous co-immunoprecipitation assays were performed to corroborate interactions. Biochemical and functional assays in human, mouse and Caenorhabditis elegans models were carried out to characterize pathway components. Thirteen FANCD2-monoubiquitinylation-positive FA cell lines excluded for genetic defects in the downstream pathway components and 300 familial BrCa patients negative for BRCA1/2 mutations were analyzed for genetic mutations. Common genetic variants were genotyped in 9,573 BRCA1/2 mutation carriers for associations with BrCa risk. RESULTS: A previously identified co-purifying protein with PALB2 was identified, MRG15 (MORF4L1 gene). Results in human, mouse and C. elegans models delineate molecular and functional relationships with BRCA2, PALB2, RAD51 and RPA1 that suggest a role for MRG15 in the repair of DNA double-strand breaks. Mrg15-deficient murine embryonic fibroblasts showed moderate sensitivity to γ-irradiation relative to controls and reduced formation of Rad51 nuclear foci. Examination of mutants of MRG15 and BRCA2 C. elegans orthologs revealed phenocopy by accumulation of RPA-1 (human RPA1) nuclear foci and aberrant chromosomal compactions in meiotic cells. However, no alterations or mutations were identified for MRG15/MORF4L1 in unclassified FA patients and BrCa familial cases. Finally, no significant associations between common MORF4L1 variants and BrCa risk for BRCA1 or BRCA2 mutation carriers were identified: rs7164529, Ptrend = 0.45 and 0.05, P2df = 0.51 and 0.14, respectively; and rs10519219, Ptrend = 0.92 and 0.72, P2df = 0.76 and 0.07, respectively. CONCLUSIONS: While the present study expands on the role of MRG15 in the control of genomic stability, weak associations cannot be ruled out for potential low-penetrance variants at MORF4L1 and BrCa risk among BRCA2 mutation carriers.


Assuntos
Neoplasias da Mama/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Animais , Neoplasias da Mama/metabolismo , Caenorhabditis elegans , Linhagem Celular , Dano ao DNA , Reparo do DNA , Anemia de Fanconi/genética , Proteína do Grupo de Complementação D2 da Anemia de Fanconi/genética , Proteína do Grupo de Complementação D2 da Anemia de Fanconi/metabolismo , Proteína do Grupo de Complementação N da Anemia de Fanconi , Feminino , Genes BRCA1 , Genes BRCA2 , Predisposição Genética para Doença , Humanos , Camundongos , Mutação , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Interferência de RNA , Rad51 Recombinase/genética , Rad51 Recombinase/metabolismo , Proteína de Replicação A/genética , Proteína de Replicação A/metabolismo , Fatores de Risco , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo , Técnicas do Sistema de Duplo-Híbrido
19.
DNA Repair (Amst) ; 10(5): 518-25, 2011 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-21466974

RESUMO

Fanconi anemia (FA) and ataxia telangiectasia (AT) share common traits such chromosomal instability and proneness to hematological cancers. Both AT and FA cell lines, and patients, are characterized by abnormally high levels of oxidative stress markers. The key FA protein FANCD2 is phosphorylated on Ser 222 by ATM after ionizing radiation (IR), thus allowing normal activation of the S-phase checkpoint, and ATM cells are known to be hypersensitive to oxidative damage. In this work we show that FANCD2 deficient cells have a defective S-phase checkpoint after Hydrogen Peroxide (H(2)O(2)) induced oxidative damage. ATM dependent phosphorylation of FANCD2 at the S222 residue is necessary for normal S-phase checkpoint activation after oxidative stress, while FANCD2 monoubiquitination at K561 is dispensable. We also show that FANCD2 is not required for base excision repair of 8-oxoG and other DNA lesions (abasic sites, uracils), while treatments that exclusively induce 8-oxoG, but not DNA double strand breaks, fail to activate FANCD2 monoubiquitination, thus indicating that the known accumulation of 8-oxoG in FA cells reflects an overproduction of ROS rather than defective processing of oxidized bases. We conclude that the handling of DNA damage after H(2)O(2)-induced oxidative stress requires the coordinated action of FANCD2 and ATM.


Assuntos
Dano ao DNA/efeitos dos fármacos , Oxidantes , 8-Hidroxi-2'-Desoxiguanosina , Animais , Ataxia Telangiectasia/fisiopatologia , Proteínas Mutadas de Ataxia Telangiectasia , Bromatos/farmacologia , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular , DNA/genética , DNA/metabolismo , Dano ao DNA/genética , Reparo do DNA/efeitos dos fármacos , Reparo do DNA/genética , Proteínas de Ligação a DNA/metabolismo , Desoxiguanosina/análogos & derivados , Desoxiguanosina/metabolismo , Anemia de Fanconi/fisiopatologia , Proteína do Grupo de Complementação D2 da Anemia de Fanconi/metabolismo , Histonas/metabolismo , Humanos , Peróxido de Hidrogênio/farmacologia , Camundongos , Oxidantes/farmacologia , Fosforilação/efeitos dos fármacos , Proteínas Serina-Treonina Quinases/metabolismo , Fase S/efeitos dos fármacos , Proteínas Supressoras de Tumor/metabolismo , Ubiquitinação/efeitos dos fármacos
20.
Nucleic Acids Res ; 39(13): 5459-73, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21421559

RESUMO

Deciphering the crosstalk between a host cell and a virus during infection is important not only to better define viral biology but also to improve our understanding of cellular processes. We identified the FANC pathway as a helper of viral replication and recombination by searching for cellular targets that are modified by adenovirus (Ad) infection and are involved in its outcome. This pathway, which is involved in the DNA damage response and checkpoint control, is altered in Fanconi anaemia, a rare cancer predisposition syndrome. We show here that Ad5 infection activates the FANC pathway independent of the classical DNA damage response. Infection with a non-replicating Ad shows that the presence of viral DNA is not sufficient to induce the monoubiquitination of FANCD2 but still activates the DNA damage response coordinated by phospho-NBS1 and phospho-CHK1. E1A expression alone fails to induce FANCD2 monoubiquitination, indicating that a productive viral infection and/or replication is required for FANC pathway activation. Our data indicate that Ad5 infection induces FANCD2 activation to promote its own replication. Specifically, we show that FANCD2 is involved in the recombination process that accompanies viral DNA replication. This study provides evidence of a DNA damage-independent function of the FANC pathway and identifies a cellular system involved in Ad5 recombination.


Assuntos
Adenoviridae/genética , Proteína do Grupo de Complementação D2 da Anemia de Fanconi/metabolismo , Recombinação Genética , Replicação Viral , Adenoviridae/fisiologia , Proteínas E1A de Adenovirus/metabolismo , Linhagem Celular , Células Cultivadas , Dano ao DNA , Replicação do DNA , Proteínas de Grupos de Complementação da Anemia de Fanconi/metabolismo , Humanos , Cinética , Ubiquitinação
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