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1.
Nat Commun ; 15(1): 3734, 2024 May 03.
Article in English | MEDLINE | ID: mdl-38702312

ABSTRACT

Mutations in DNA damage response (DDR) factors are associated with human infertility, which affects up to 15% of the population. The DDR is required during germ cell development and meiosis. One pathway implicated in human fertility is DNA translesion synthesis (TLS), which allows replication impediments to be bypassed. We find that TLS is essential for pre-meiotic germ cell development in the embryo. Loss of the central TLS component, REV1, significantly inhibits the induction of human PGC-like cells (hPGCLCs). This is recapitulated in mice, where deficiencies in TLS initiation (Rev1-/- or PcnaK164R/K164R) or extension (Rev7 -/-) result in a > 150-fold reduction in the number of primordial germ cells (PGCs) and complete sterility. In contrast, the absence of TLS does not impact the growth, function, or homeostasis of somatic tissues. Surprisingly, we find a complete failure in both activation of the germ cell transcriptional program and in DNA demethylation, a critical step in germline epigenetic reprogramming. Our findings show that for normal fertility, DNA repair is required not only for meiotic recombination but for progression through the earliest stages of germ cell development in mammals.


Subject(s)
DNA Demethylation , DNA Repair , DNA-Directed DNA Polymerase , Germ Cells , Animals , Humans , Mice , Germ Cells/metabolism , DNA-Directed DNA Polymerase/metabolism , DNA-Directed DNA Polymerase/genetics , Male , Nucleotidyltransferases/metabolism , Nucleotidyltransferases/genetics , Female , DNA Damage , Mice, Knockout , Meiosis/genetics , DNA Replication , Proliferating Cell Nuclear Antigen/metabolism , Epigenesis, Genetic , Translesion DNA Synthesis
2.
Nat Commun ; 15(1): 2518, 2024 Mar 21.
Article in English | MEDLINE | ID: mdl-38514641

ABSTRACT

DNA repair deficiency can lead to segmental phenotypes in humans and mice, in which certain tissues lose homeostasis while others remain seemingly unaffected. This may be due to different tissues facing varying levels of damage or having different reliance on specific DNA repair pathways. However, we find that the cellular response to DNA damage determines different tissue-specific outcomes. Here, we use a mouse model of the human XPF-ERCC1 progeroid syndrome (XFE) caused by loss of DNA repair. We find that p53, a central regulator of the cellular response to DNA damage, regulates tissue dysfunction in Ercc1-/- mice in different ways. We show that ablation of p53 rescues the loss of hematopoietic stem cells, and has no effect on kidney, germ cell or brain dysfunction, but exacerbates liver pathology and polyploidisation. Mechanistically, we find that p53 ablation led to the loss of cell-cycle regulation in the liver, with reduced p21 expression. Eventually, p16/Cdkn2a expression is induced, serving as a fail-safe brake to proliferation in the absence of the p53-p21 axis. Taken together, our data show that distinct and tissue-specific functions of p53, in response to DNA damage, play a crucial role in regulating tissue-specific phenotypes.


Subject(s)
Tumor Suppressor Protein p53 , Xeroderma Pigmentosum , Animals , Humans , Mice , DNA Damage , DNA Repair , DNA-Binding Proteins/metabolism , Tumor Suppressor Protein p53/metabolism , Xeroderma Pigmentosum/genetics
3.
Nat Struct Mol Biol ; 30(10): 1434-1445, 2023 10.
Article in English | MEDLINE | ID: mdl-37580626

ABSTRACT

Long interspersed nuclear element 1 (LINE-1) is the only autonomous retrotransposon in humans and new integrations are a major source of genetic variation between individuals. These events can also lead to de novo germline mutations, giving rise to heritable genetic diseases. Recently, a role for DNA repair in regulating these events has been identified. Here we find that Fanconi anemia (FA) DNA crosslink repair factors act in a common pathway to prevent retrotransposition. We purify recombinant SLX4-XPF-ERCC1, the crosslink repair incision complex, and find that it cleaves putative nucleic acid intermediates of retrotransposition. Mice deficient in upstream crosslink repair signaling (FANCA), a downstream component (FANCD2) or the nuclease XPF-ERCC1 show increased LINE-1 retrotransposition in vivo. Organisms limit retrotransposition through transcriptional silencing but this protection is attenuated during early development leaving the zygote vulnerable. We find that during this window of vulnerability, DNA crosslink repair acts as a failsafe to prevent retrotransposition. Together, our results indicate that the FA DNA crosslink repair pathway acts together to protect against mutation by restricting LINE-1 retrotransposition.


Subject(s)
Fanconi Anemia , Humans , Mice , Animals , Fanconi Anemia/genetics , DNA-Binding Proteins/metabolism , DNA Repair , DNA Damage , Fanconi Anemia Complementation Group D2 Protein/genetics , DNA/genetics
4.
Nucleic Acids Res ; 51(10): 4791-4813, 2023 06 09.
Article in English | MEDLINE | ID: mdl-36919611

ABSTRACT

Recycling and de-novo deposition of histones during DNA replication is a critical challenge faced by eukaryotic cells and is coordinated by histone chaperones. Spermatogenesis is highly regulated sophisticated process necessitating not only histone modification but loading of testis specific histone variants. Here, we show that Germ Cell Nuclear Acidic protein (GCNA), a germ cell specific protein in adult mice, can bind histones and purified GCNA exhibits histone chaperone activity. GCNA associates with the DNA replication machinery and supports progression through S-phase in murine undifferentiated spermatogonia (USGs). Whilst GCNA is dispensable for embryonic germ cell development, it is required for the maintenance of the USG pool and for long-term production of sperm. Our work describes the role of a germ cell specific histone chaperone in USGs maintenance in mice. These findings provide a mechanistic basis for the male infertility observed in patients carrying GCNA mutations.


Subject(s)
Histones , Nuclear Proteins , Male , Mice , Animals , Histones/metabolism , Nuclear Proteins/metabolism , Semen/metabolism , Testis/metabolism , Spermatogenesis/genetics , Spermatogonia/metabolism , Cell Differentiation/genetics , Stem Cells/metabolism
5.
Nat Commun ; 13(1): 745, 2022 02 08.
Article in English | MEDLINE | ID: mdl-35136057

ABSTRACT

Formaldehyde (FA) is a ubiquitous endogenous and environmental metabolite that is thought to exert cytotoxicity through DNA and DNA-protein crosslinking, likely contributing to the onset of the human DNA repair condition Fanconi Anaemia. Mutations in the genes coding for FA detoxifying enzymes underlie a human inherited bone marrow failure syndrome (IBMFS), even in the presence of functional DNA repair, raising the question of whether FA causes relevant cellular damage beyond genotoxicity. Here, we report that FA triggers cellular redox imbalance in human cells and in Caenorhabditis elegans. Mechanistically, FA reacts with the redox-active thiol group of glutathione (GSH), altering the GSH:GSSG ratio and causing oxidative stress. FA cytotoxicity is prevented by the enzyme alcohol dehydrogenase 5 (ADH5/GSNOR), which metabolizes FA-GSH products, lastly yielding reduced GSH. Furthermore, we show that GSH synthesis protects human cells from FA, indicating an active role of GSH in preventing FA toxicity. These findings might be relevant for patients carrying mutations in FA-detoxification systems and could suggest therapeutic benefits from thiol-rich antioxidants like N-acetyl-L-cysteine.


Subject(s)
Aldehyde Oxidoreductases/metabolism , Caenorhabditis elegans Proteins/metabolism , Fanconi Anemia/metabolism , Formaldehyde/toxicity , Glutathione/metabolism , Aldehyde Oxidoreductases/genetics , Animals , Caenorhabditis elegans , Caenorhabditis elegans Proteins/genetics , DNA Damage , Disease Models, Animal , Fanconi Anemia/genetics , Fanconi Anemia Complementation Group D2 Protein/genetics , Fanconi Anemia Complementation Group D2 Protein/metabolism , Formaldehyde/metabolism , Gene Knockout Techniques , HCT116 Cells , Humans , Oxidation-Reduction , Oxidative Stress
6.
Nature ; 600(7887): 158-163, 2021 12.
Article in English | MEDLINE | ID: mdl-34819667

ABSTRACT

Endogenous DNA damage can perturb transcription, triggering a multifaceted cellular response that repairs the damage, degrades RNA polymerase II and shuts down global transcription1-4. This response is absent in the human disease Cockayne syndrome, which is caused by loss of the Cockayne syndrome A (CSA) or CSB proteins5-7. However, the source of endogenous DNA damage and how this leads to the prominent degenerative features of this disease remain unknown. Here we find that endogenous formaldehyde impedes transcription, with marked physiological consequences. Mice deficient in formaldehyde clearance (Adh5-/-) and CSB (Csbm/m; Csb is also known as Ercc6) develop cachexia and neurodegeneration, and succumb to kidney failure, features that resemble human Cockayne syndrome. Using single-cell RNA sequencing, we find that formaldehyde-driven transcriptional stress stimulates the expression of the anorexiogenic peptide GDF15 by a subset of kidney proximal tubule cells. Blocking this response with an anti-GDF15 antibody alleviates cachexia in Adh5-/-Csbm/m mice. Therefore, CSB provides protection to the kidney and brain against DNA damage caused by endogenous formaldehyde, while also suppressing an anorexic endocrine signal. The activation of this signal might contribute to the cachexia observed in Cockayne syndrome as well as chemotherapy-induced anorectic weight loss. A plausible evolutionary purpose for such a response is to ensure aversion to genotoxins in food.


Subject(s)
Cockayne Syndrome , DNA Damage , Formaldehyde/adverse effects , Stress, Physiological/drug effects , Transcription, Genetic/drug effects , Alcohol Dehydrogenase/deficiency , Alcohol Dehydrogenase/metabolism , Animals , Brain/drug effects , Brain/metabolism , Brain/pathology , Cachexia/complications , Cockayne Syndrome/chemically induced , Cockayne Syndrome/complications , Cockayne Syndrome/genetics , Cockayne Syndrome/pathology , DNA Repair Enzymes/deficiency , Disease Models, Animal , Female , Formaldehyde/metabolism , Growth Differentiation Factor 15/antagonists & inhibitors , Growth Differentiation Factor 15/biosynthesis , Growth Differentiation Factor 15/genetics , Kidney Tubules, Proximal/drug effects , Kidney Tubules, Proximal/metabolism , Kidney Tubules, Proximal/pathology , Male , Mice , Poly-ADP-Ribose Binding Proteins/deficiency , Renal Insufficiency/complications , Transcription, Genetic/genetics
7.
Nat Genet ; 51(8): 1283-1294, 2019 08.
Article in English | MEDLINE | ID: mdl-31367016

ABSTRACT

Germline de novo mutations are the basis of evolutionary diversity but also of genetic disease. However, the molecular origin, mechanisms and timing of germline mutagenesis are not fully understood. Here, we define a fundamental role for DNA interstrand cross-link repair in the germline. This repair process is essential for primordial germ cell (PGC) maturation during embryonic development. Inactivation of cross-link repair leads to genetic instability that is restricted to PGCs within the genital ridge during a narrow temporal window. Having successfully activated the PGC transcriptional program, a potent quality control mechanism detects and drives damaged PGCs into apoptosis. Therefore, these findings define a source of DNA damage and the nature of the subsequent DNA repair response in germ cells, which ensures faithful transmission of the genome between generations.


Subject(s)
Cell Differentiation , DNA Repair , DNA/chemistry , Genomic Instability , Germ Cells/cytology , Meiosis/physiology , Aldehydes/metabolism , Aldehydes/toxicity , Animals , Apoptosis/drug effects , Cross-Linking Reagents , DNA/genetics , DNA Damage , DNA-Binding Proteins/physiology , Endonucleases/physiology , Female , Fertility , Genome , Germ Cells/physiology , Male , Mice , Mice, Inbred C57BL , Mice, Knockout
8.
Nature ; 553(7687): 171-177, 2018 01 11.
Article in English | MEDLINE | ID: mdl-29323295

ABSTRACT

Haematopoietic stem cells renew blood. Accumulation of DNA damage in these cells promotes their decline, while misrepair of this damage initiates malignancies. Here we describe the features and mutational landscape of DNA damage caused by acetaldehyde, an endogenous and alcohol-derived metabolite. This damage results in DNA double-stranded breaks that, despite stimulating recombination repair, also cause chromosome rearrangements. We combined transplantation of single haematopoietic stem cells with whole-genome sequencing to show that this damage occurs in stem cells, leading to deletions and rearrangements that are indicative of microhomology-mediated end-joining repair. Moreover, deletion of p53 completely rescues the survival of aldehyde-stressed and mutated haematopoietic stem cells, but does not change the pattern or the intensity of genome instability within individual stem cells. These findings characterize the mutation of the stem-cell genome by an alcohol-derived and endogenous source of DNA damage. Furthermore, we identify how the choice of DNA-repair pathway and a stringent p53 response limit the transmission of aldehyde-induced mutations in stem cells.


Subject(s)
Acetaldehyde/metabolism , DNA Breaks, Double-Stranded/drug effects , Ethanol/metabolism , Ethanol/pharmacology , Genomic Instability/drug effects , Hematopoietic Stem Cells/drug effects , Hematopoietic Stem Cells/pathology , Mutation , Alcohol Dehydrogenase/deficiency , Alcohol Dehydrogenase/genetics , Alcohol Dehydrogenase/metabolism , Animals , Cell Survival/drug effects , DNA End-Joining Repair , Ethanol/administration & dosage , Fanconi Anemia/genetics , Fanconi Anemia/metabolism , Fanconi Anemia/pathology , Fanconi Anemia Complementation Group D2 Protein/deficiency , Fanconi Anemia Complementation Group D2 Protein/genetics , Fanconi Anemia Complementation Group D2 Protein/metabolism , Female , Gene Deletion , Genes, p53/genetics , Hematopoietic Stem Cell Transplantation , Hematopoietic Stem Cells/metabolism , Ku Autoantigen/metabolism , Male , Mice , Mice, Inbred C57BL , Recombinational DNA Repair/drug effects , Tumor Suppressor Protein p53/deficiency , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , Whole Genome Sequencing
10.
Mol Cell ; 60(1): 177-88, 2015 Oct 01.
Article in English | MEDLINE | ID: mdl-26412304

ABSTRACT

Endogenous formaldehyde is produced by numerous biochemical pathways fundamental to life, and it can crosslink both DNA and proteins. However, the consequences of its accumulation are unclear. Here we show that endogenous formaldehyde is removed by the enzyme alcohol dehydrogenase 5 (ADH5/GSNOR), and Adh5(-/-) mice therefore accumulate formaldehyde adducts in DNA. The repair of this damage is mediated by FANCD2, a DNA crosslink repair protein. Adh5(-/-)Fancd2(-/-) mice reveal an essential requirement for these protection mechanisms in hematopoietic stem cells (HSCs), leading to their depletion and precipitating bone marrow failure. More widespread formaldehyde-induced DNA damage also causes karyomegaly and dysfunction of hepatocytes and nephrons. Bone marrow transplantation not only rescued hematopoiesis but, surprisingly, also preserved nephron function. Nevertheless, all of these animals eventually developed fatal malignancies. Formaldehyde is therefore an important source of endogenous DNA damage that is counteracted in mammals by a conserved protection mechanism.


Subject(s)
Alcohol Dehydrogenase/metabolism , Carcinogens/metabolism , Fanconi Anemia Complementation Group D2 Protein/metabolism , Formaldehyde/metabolism , Mutagens/metabolism , Alcohol Dehydrogenase/genetics , Animals , Cells, Cultured , DNA Adducts/metabolism , Fanconi Anemia Complementation Group D2 Protein/genetics , Gene Knockout Techniques , Hematopoietic Stem Cells/cytology , Hematopoietic Stem Cells/metabolism , Hematopoietic Stem Cells/pathology , Kidney/metabolism , Kidney/pathology , Liver/metabolism , Liver/pathology , Mice
11.
Cell Stem Cell ; 16(2): 111-2, 2015 Feb 05.
Article in English | MEDLINE | ID: mdl-25658366

ABSTRACT

For more than 60 years, we have known that the incidence of certain common human cancers increases with age. Recently in Science, Tomasetti and Vogelstein (2015) refined this model by providing a potential explanation, arguing that early random mutational events within individual stem cells of regenerating organs may underlie this correlation.


Subject(s)
Cell Division/genetics , Neoplasms/epidemiology , Neoplasms/genetics , Stem Cells/physiology , Humans
12.
Mol Cell ; 55(6): 807-817, 2014 Sep 18.
Article in English | MEDLINE | ID: mdl-25155611

ABSTRACT

Maternal metabolism provides essential nutrients to enable embryonic development. However, both mother and embryo produce reactive metabolites that can damage DNA. Here we discover how the embryo is protected from these genotoxins. Pregnant mice lacking Aldh2, a key enzyme that detoxifies reactive aldehydes, cannot support the development of embryos lacking the Fanconi anemia DNA repair pathway gene Fanca. Remarkably, transferring Aldh2(-/-)Fanca(-/-) embryos into wild-type mothers suppresses developmental defects and rescues embryonic lethality. These rescued neonates have severely depleted hematopoietic stem and progenitor cells, indicating that despite intact maternal aldehyde catabolism, fetal Aldh2 is essential for hematopoiesis. Hence, maternal and fetal aldehyde detoxification protects the developing embryo from DNA damage. Failure of this genome preservation mechanism might explain why birth defects and bone marrow failure occur in Fanconi anemia, and may have implications for fetal well-being in the many women in Southeast Asia that are genetically deficient in ALDH2.


Subject(s)
Acetaldehyde/metabolism , Aldehyde Dehydrogenase/genetics , Aldehyde Dehydrogenase/metabolism , Embryo, Mammalian/metabolism , Ethanol/toxicity , Fanconi Anemia Complementation Group A Protein/genetics , Fanconi Anemia/pathology , Acetaldehyde/toxicity , Aldehyde Dehydrogenase 1 Family , Aldehyde Dehydrogenase, Mitochondrial , Animals , Animals, Newborn , DNA Damage , Disease Models, Animal , Embryo, Mammalian/embryology , Female , Genome , Hematopoietic Stem Cells/metabolism , Humans , Isoenzymes/genetics , Isoenzymes/metabolism , Mice , Mice, Inbred C57BL , Pregnancy , Retinal Dehydrogenase/genetics , Retinal Dehydrogenase/metabolism
13.
Mol Cell ; 54(3): 472-84, 2014 May 08.
Article in English | MEDLINE | ID: mdl-24726326

ABSTRACT

SLX4 binds to three nucleases (XPF-ERCC1, MUS81-EME1, and SLX1), and its deficiency leads to genomic instability, sensitivity to DNA crosslinking agents, and Fanconi anemia. However, it is not understood how SLX4 and its associated nucleases act in DNA crosslink repair. Here, we uncover consequences of mouse Slx4 deficiency and reveal its function in DNA crosslink repair. Slx4-deficient mice develop epithelial cancers and have a contracted hematopoietic stem cell pool. The N-terminal domain of SLX4 (mini-SLX4) that only binds to XPF-ERCC1 is sufficient to confer resistance to DNA crosslinking agents. Recombinant mini-SLX4 enhances XPF-ERCC1 nuclease activity up to 100-fold, directing specificity toward DNA forks. Mini-SLX4-XPF-ERCC1 also vigorously stimulates dual incisions around a DNA crosslink embedded in a synthetic replication fork, an essential step in the repair of this lesion. These observations define vertebrate SLX4 as a tumor suppressor, which activates XPF-ERCC1 nuclease specificity in DNA crosslink repair.


Subject(s)
DNA Repair , DNA-Binding Proteins/metabolism , Endonucleases/metabolism , Recombinases/physiology , Animals , Base Sequence , Bone Marrow Cells/pathology , DNA Adducts/chemistry , DNA Damage , DNA-Binding Proteins/chemistry , Endonucleases/chemistry , Hematopoietic Stem Cells/pathology , Mice , Mice, Inbred C57BL , Mice, Transgenic , Neoplasms/enzymology , Nucleic Acid Conformation , Tumor Suppressor Proteins
15.
Hum Mutat ; 34(1): 70-3, 2013 Jan.
Article in English | MEDLINE | ID: mdl-22911665

ABSTRACT

SLX4/FANCP is a recently discovered novel disease gene for Fanconi anemia (FA), a rare recessive disorder characterized by chromosomal instability and increased cancer susceptibility. Three of the 15 FA genes are breast cancer susceptibility genes in heterozygous mutation carriers--BRCA2, PALB2, and BRIP1. To investigate if defects in SLX4 also predispose to breast cancer, the gene was sequenced in a cohort of 729 BRCA1/BRCA2-negative familial breast cancer cases. We identified a single splice site mutation (c.2013+2T>A), which causes a frameshift by skipping of exon 8. We also identified 39 missense variants, four of which were selected for functional testing in a Mitomycin C-induced growth inhibition assay, and appeared indistinguishable from wild type. Although this is the first study that describes a truncating SLX4 mutation in breast cancer patients, our data indicate that germline mutations in SLX4 are very rare and are unlikely to make a significant contribution to familial breast cancer.


Subject(s)
Breast Neoplasms, Male/genetics , Breast Neoplasms/genetics , Mutation , Recombinases/genetics , Adult , Aged , Aged, 80 and over , Cohort Studies , DNA Mutational Analysis , Family Health , Fanconi Anemia/genetics , Female , Genetic Predisposition to Disease/genetics , Humans , Male , Middle Aged , Mutation, Missense , RNA Splice Sites/genetics
16.
Nature ; 489(7417): 571-5, 2012 Sep 27.
Article in English | MEDLINE | ID: mdl-22922648

ABSTRACT

Haematopoietic stem cells (HSCs) regenerate blood cells throughout the lifespan of an organism. With age, the functional quality of HSCs declines, partly owing to the accumulation of damaged DNA. However, the factors that damage DNA and the protective mechanisms that operate in these cells are poorly understood. We have recently shown that the Fanconi anaemia DNA-repair pathway counteracts the genotoxic effects of reactive aldehydes. Mice with combined inactivation of aldehyde catabolism (through Aldh2 knockout) and the Fanconi anaemia DNA-repair pathway (Fancd2 knockout) display developmental defects, a predisposition to leukaemia, and are susceptible to the toxic effects of ethanol-an exogenous source of acetaldehyde. Here we report that aged Aldh2(-/-) Fancd2(-/-) mutant mice that do not develop leukaemia spontaneously develop aplastic anaemia, with the concomitant accumulation of damaged DNA within the haematopoietic stem and progenitor cell (HSPC) pool. Unexpectedly, we find that only HSPCs, and not more mature blood precursors, require Aldh2 for protection against acetaldehyde toxicity. Additionally, the aldehyde-oxidizing activity of HSPCs, as measured by Aldefluor stain, is due to Aldh2 and correlates with this protection. Finally, there is more than a 600-fold reduction in the HSC pool of mice deficient in both Fanconi anaemia pathway-mediated DNA repair and acetaldehyde detoxification. Therefore, the emergence of bone marrow failure in Fanconi anaemia is probably due to aldehyde-mediated genotoxicity restricted to the HSPC pool. These findings identify a new link between endogenous reactive metabolites and DNA damage in HSCs, and define the protective mechanisms that counteract this threat.


Subject(s)
Aldehydes/toxicity , Hematopoietic Stem Cells/cytology , Hematopoietic Stem Cells/drug effects , Mutagens/toxicity , Acetaldehyde/metabolism , Acetaldehyde/toxicity , Aging , Aldehyde Dehydrogenase/deficiency , Aldehyde Dehydrogenase/genetics , Aldehyde Dehydrogenase/metabolism , Aldehyde Dehydrogenase, Mitochondrial , Aldehydes/metabolism , Animals , Bone Marrow/pathology , DNA Damage/drug effects , DNA Damage/genetics , DNA Repair , Ethanol/toxicity , Fanconi Anemia/pathology , Fanconi Anemia Complementation Group D2 Protein/deficiency , Fanconi Anemia Complementation Group D2 Protein/genetics , Female , Hematopoietic Stem Cells/enzymology , Hematopoietic Stem Cells/metabolism , Kaplan-Meier Estimate , Leukemia/metabolism , Leukemia/pathology , Male , Mice , Mice, Inbred C57BL , Mice, Knockout
17.
J Pathol ; 226(2): 326-37, 2012 Jan.
Article in English | MEDLINE | ID: mdl-21956823

ABSTRACT

Fanconi anaemia (FA) is a rare, autosomal recessive, genetically complex, DNA repair deficiency syndrome in man. Patients with FA exhibit a heterogeneous spectrum of clinical features. The most significant and consistent phenotypic characteristics are stem cell loss, causing progressive bone marrow failure and sterility, diverse developmental abnormalities and a profound predisposition to neoplasia. To date, 15 genes have been identified, biallelic disruption of any one of which results in this clinically defined syndrome. It is now apparent that all 15 gene products act in a common process to maintain genome stability. At the molecular level, a fundamental defect in DNA repair underlies this complex phenotype. Cells derived from FA patients spontaneously accumulate broken chromosomes and exhibit a marked sensitivity to DNA-damaging chemotherapeutic agents. Despite complementation analysis defining many components of the FA DNA repair pathway, no direct link to DNA metabolism was established until recently. First, it is now evident that the FA pathway is required to make incisions at the site of damaged DNA. Second, a specific component of the FA pathway has been identified that regulates nucleases previously implicated in DNA interstrand crosslink repair. Taken together, these data provide genetic and biochemical evidence that the FA pathway is a bona fide DNA repair pathway that directly mediates DNA repair transactions, thereby elucidating the specific molecular defect in human Fanconi anaemia.


Subject(s)
DNA Damage/genetics , DNA Repair/genetics , Fanconi Anemia Complementation Group Proteins/genetics , Fanconi Anemia/genetics , DNA Replication , Endonucleases/physiology , Genetic Predisposition to Disease , Hematopoietic Stem Cells/physiology , Humans , Neoplasms/genetics
18.
Cancer Cell ; 20(6): 693-5, 2011 Dec 13.
Article in English | MEDLINE | ID: mdl-22172717

ABSTRACT

BRCA1 is a crucial human breast and ovarian cancer tumor suppressor gene. The article by Drost et al. in this issue of Cancer Cell together with a recent paper in Science now provide a clearer picture of how this large and complex protein suppresses tumorigenesis.

19.
Nat Struct Mol Biol ; 18(12): 1432-4, 2011 Nov 13.
Article in English | MEDLINE | ID: mdl-22081012

ABSTRACT

Metabolism is predicted to generate formaldehyde, a toxic, simple, reactive aldehyde that can damage DNA. Here we report a synthetic lethal interaction in avian cells between ADH5, encoding the main formaldehyde-detoxifying enzyme, and the Fanconi anemia (FA) DNA-repair pathway. These results define a fundamental role for the combined action of formaldehyde catabolism and DNA cross-link repair in vertebrate cell survival.


Subject(s)
DNA Repair , Fanconi Anemia/metabolism , Formaldehyde/metabolism , Aldehyde Oxidoreductases/genetics , Animals , Cell Line , Chickens/genetics , Fanconi Anemia/genetics , Fanconi Anemia Complementation Group C Protein/genetics , Fanconi Anemia Complementation Group C Protein/physiology , Fanconi Anemia Complementation Group L Protein/genetics , Fanconi Anemia Complementation Group L Protein/physiology , Gene Knockout Techniques , Metabolic Networks and Pathways
20.
Nature ; 475(7354): 53-8, 2011 Jul 06.
Article in English | MEDLINE | ID: mdl-21734703

ABSTRACT

Reactive aldehydes are common carcinogens. They are also by-products of several metabolic pathways and, without enzymatic catabolism, may accumulate and cause DNA damage. Ethanol, which is metabolised to acetaldehyde, is both carcinogenic and teratogenic in humans. Here we find that the Fanconi anaemia DNA repair pathway counteracts acetaldehyde-induced genotoxicity in mice. Our results show that the acetaldehyde-catabolising enzyme Aldh2 is essential for the development of Fancd2(-/-) embryos. Nevertheless, acetaldehyde-catabolism-competent mothers (Aldh2(+/-)) can support the development of double-mutant (Aldh2(-/-)Fancd2(-/-)) mice. However, these embryos are unusually sensitive to ethanol exposure in utero, and ethanol consumption by postnatal double-deficient mice rapidly precipitates bone marrow failure. Lastly, Aldh2(-/-)Fancd2(-/-) mice spontaneously develop acute leukaemia. Acetaldehyde-mediated DNA damage may critically contribute to the genesis of fetal alcohol syndrome in fetuses, as well as to abnormal development, haematopoietic failure and cancer predisposition in Fanconi anaemia patients.


Subject(s)
Aldehydes/antagonists & inhibitors , Aldehydes/toxicity , Fanconi Anemia Complementation Group D2 Protein/metabolism , Acetaldehyde/metabolism , Acetaldehyde/toxicity , Aldehyde Dehydrogenase/deficiency , Aldehyde Dehydrogenase/genetics , Aldehyde Dehydrogenase/metabolism , Aldehyde Dehydrogenase, Mitochondrial , Aldehydes/metabolism , Alleles , Animals , B-Lymphocytes/drug effects , B-Lymphocytes/metabolism , Bone Marrow/drug effects , Bone Marrow/pathology , Bone Marrow/physiopathology , Cell Line , Cell Survival/drug effects , Chickens , Clone Cells/drug effects , DNA Damage/genetics , DNA Repair/genetics , Embryo Loss/chemically induced , Embryo Loss/etiology , Embryo, Mammalian/abnormalities , Embryo, Mammalian/drug effects , Embryo, Mammalian/embryology , Ethanol/metabolism , Ethanol/toxicity , Fanconi Anemia/genetics , Fanconi Anemia/pathology , Fanconi Anemia Complementation Group D2 Protein/deficiency , Fanconi Anemia Complementation Group D2 Protein/genetics , Female , Fetal Alcohol Spectrum Disorders/etiology , Gene Deletion , Genes, Essential , Hematopoiesis/drug effects , Male , Mice , Mice, Inbred C57BL , Precursor Cell Lymphoblastic Leukemia-Lymphoma/chemically induced , Precursor Cell Lymphoblastic Leukemia-Lymphoma/etiology , Pregnancy , Teratogens/metabolism , Teratogens/toxicity , Weaning
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