يعرض 1 - 10 نتائج من 161 نتيجة بحث عن '"Alain Sarasin"', وقت الاستعلام: 0.85s تنقيح النتائج
  1. 1
    دورية أكاديمية

    المصدر: Frontiers in Genetics, Vol 12 (2022)

    الوصف: Xeroderma pigmentosum (XP) is a rare genetic condition in which exposure to sunlight leads to a high tumor incidence due to defective DNA repair machinery. Herein, we investigated seven patients clinically diagnosed with XP living in a small city, Montanhas (Rio Grande do Norte), in the Northeast region of Brazil. We performed high-throughput sequencing and, surprisingly, identified two different mutated genes. Six patients carry a novel homozygote mutation in the POLH/XPV gene, c.672_673insT (p.Leu225Serfs*33), while one patient carries a homozygote mutation in the XPC gene, c.2251-1G>C. This latter mutation was previously described in Southeastern Africa (Comoro Island and Mozambique), Pakistan, and in a high incidence in Brazil. The XP-C patient had the first symptoms before the first year of life with aggressive ophthalmologic tumor progression and a melanoma onset at 7 years of age. The XP-V patients presented a milder phenotype with later onset of the disorder (mean age of 16 years old), and one of the six XP-V patients developed melanoma at 72 years. The photoprotection is minimal among them, mainly for the XP-V patients. The differences in the disease severity between XP-C (more aggressive) and XP-V (milder) patients are obvious and point to the major role of photoprotection in the XPs. We estimate that the incidence of XP patients at Montanhas can be higher, but with no diagnosis, due to poor health assistance. Patients still suffer from the stigmatization of the condition, impairing diagnosis, education for sun protection, and medical care.

    وصف الملف: electronic resource

  2. 2
    دورية أكاديمية

    المصدر: Genetics and Molecular Biology, Vol 43, Iss 1 suppl 1 (2019)

    الوصف: Abstract Xeroderma pigmentosum (XP) is a rare, genetic, autosomal nucleotide excision repair-deficient disease characterized by sun-sensitivity and early appearance of skin and ocular tumors. Thirty-two black-skinned XP from Comoros, located in the Indian Ocean, were counted, rendering this area the highest world prevalence of XP. These patients exhibited a new homozygous XPC mutation at the 3’-end of the intron12 (IVS 12-1G>C) leading to the absence of XPC protein. This mutation, characteristic of the consanguineous Comorian families, is associated with a founder effect with an estimated age of about 800 years. Analysis of mt-DNA and Y-chromosome identified the haplogroups of patients, who are derived from the Bantu people. Although the four Comorian islands were populated by the same individuals during the 7-10th centuries, XP was found now only in the Comorian island of Anjouan. To avoid the slavery process caused by the arrival of the Arabs around the 11-13th centuries, inhabitants of Anjouan, including XP-heterozygotes, hid inland of the island protected by volcanoes. This population lived with an endogamic style, without connection with the other islands. XP patients still live in the same isolated villages as their ancestries. Local history and geography may, thus, explain the high incidence of XP located exclusively in one island.

    وصف الملف: electronic resource

  3. 3
    دورية أكاديمية

    المصدر: PLoS Genetics, Vol 5, Iss 7, p e1000577 (2009)

    مصطلحات موضوعية: Genetics, QH426-470

    الوصف: Most of the somatic cells of adult metazoans, including mammals, do not undergo continuous cycles of replication. Instead, they are quiescent and devote most of their metabolic activity to gene expression. The mutagenic consequences of exposure to DNA-damaging agents are well documented, but less is known about the impact of DNA lesions on transcription. To investigate this impact, we developed a luciferase-based expression system. This system consists of two types of construct composed of a DNA template containing an 8-oxoguanine, paired either with a thymine or a cytosine, placed at defined positions along the transcribed strand of the reporter gene. Analyses of luciferase gene expression from the two types of construct showed that efficient but error-prone transcriptional bypass of 8-oxoguanine occurred in vivo, and that this lesion was not repaired by the transcription-coupled repair machinery in mammalian cells. The analysis of luciferase activity expressed from 8OG:T-containing constructs indicated that the magnitude of erroneous transcription events involving 8-oxoguanine depended on the sequence contexts surrounding the lesion. Additionally, sequencing of the transcript population expressed from these constructs showed that RNA polymerase II mostly inserted an adenine opposite to 8-oxoguanine. Analysis of luciferase expression from 8OG:C-containing constructs showed that the generated aberrant mRNAs led to the production of mutant proteins with the potential to induce a long-term phenotypical change. These findings reveal that erroneous transcription over DNA lesions may induce phenotypical changes with the potential to alter the fate of non-replicating cells.

    وصف الملف: electronic resource

  4. 4

    المساهمون: Intégrité du génome et cancers (IGC), Institut Gustave Roussy (IGR)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

    المصدر: Scientific Reports, Vol 10, Iss 1, Pp 1-11 (2020)
    Scientific Reports
    Scientific Reports, Nature Publishing Group, 2020, 10 (1), ⟨10.1038/s41598-020-58180-7⟩
    Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual)
    Universidade de São Paulo (USP)
    instacron:USP

    الوصف: Somatic hypermutation of immunoglobulin genes is a highly mutagenic process that is B cell-specific and occurs during antigen-driven responses leading to antigen specificity and antibody affinity maturation. Mutations at the Ig locus are initiated by Activation-Induced cytidine Deaminase and are equally distributed at G/C and A/T bases. This requires the establishment of error-prone repair pathways involving the activity of several low fidelity DNA polymerases. In the physiological context, the G/C base pair mutations involve multiple error-prone DNA polymerases, while the generation of mutations at A/T base pairs depends exclusively on the activity of DNA polymerase η. Using two large cohorts of individuals with xeroderma pigmentosum variant (XP-V), we report that the pattern of mutations at Ig genes becomes highly enriched with large deletions. This observation is more striking for patients older than 50 years. We propose that the absence of Pol η allows the recruitment of other DNA polymerases that profoundly affect the Ig genomic landscape.

  5. 5

    الوصف: Xeroderma pigmentosum (XP) is a rare genetic condition in which exposure to sunlight leads to a high tumor incidence due to defective DNA repair machinery. Herein, we investigated seven patients clinically diagnosed with XP living in a small city, Montanhas (Rio Grande do Norte), in the Northeast region of Brazil. We performed high-throughput sequencing and, surprisingly, identified two different mutated genes. Six patients carry a novel homozygote mutation in the POLH/XPV gene, c.672_673insT (p.Leu225Serfs*33), while one patient carries a homozygote mutation in the XPC gene, c.2251-1G>C. This latter mutation was previously described in Southeastern Africa (Comoro Island and Mozambique), Pakistan, and in a high incidence in Brazil. The XP-C patient had the first symptoms before the first year of life with aggressive ophthalmologic tumor progression and a melanoma onset at 7 years of age. The XP-V patients presented a milder phenotype with later onset of the disorder (mean age of 16 years old), and one of the six XP-V patients developed melanoma at 72 years. The photoprotection is minimal among them, mainly for the XP-V patients. The differences in the disease severity between XP-C (more aggressive) and XP-V (milder) patients are obvious and point to the major role of photoprotection in the XPs. We estimate that the incidence of XP patients at Montanhas can be higher, but with no diagnosis, due to poor health assistance. Patients still suffer from the stigmatization of the condition, impairing diagnosis, education for sun protection, and medical care.

  6. 6

    المساهمون: Cellules Souches et Développement / Stem Cells and Development, Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS), Sup'Biotech, Hub Bioinformatique et Biostatistique - Bioinformatics and Biostatistics HUB, Karolinska Institutet [Stockholm], University hospital - Policlinico S.Orsola-Malpighi [Bologna, Italy], CNR Institute of Molecular Genetics 'Luigi Luca Cavalli-Sforza', Istituto Ortopedico Rizzoli [Bologna, Italy], University of California (UC), Institut Gustave Roussy (IGR), Stabilité Génétique et Oncogenèse (UMR 8200), Université Paris-Sud - Paris 11 (UP11)-Institut Gustave Roussy (IGR)-Centre National de la Recherche Scientifique (CNRS), Lobachevsky State University [Nizhni Novgorod], IRCCS Istituto delle Scienze Neurologiche di Bologna [Bologna, Italy], Ospedale Bellaria [Bologna, Italy], This work was supported by Agence Nationale de la Recherche (grant CS_AGE, aapg2019), DARRI (Institut Pasteur R&D, grant DISAGE, PasteurInnov2014), Programmes Transversales de Recherche, Institut Pasteur (grant PTR111-2017), Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), University of California

    الوصف: Cockayne syndrome (CS) and UV-sensitivity syndrome (UVSS) are rare genetic disorders caused by mutation of the DNA repair and chromatin remodelling proteins CSA or CSB, but only CS patients display a progeroid and neurodegenerative phenotype. As epigenetic modifications constitute a well-established hallmark of ageing, we characterized genome-wide DNA methylation (DNAm) of fibroblasts from CS versus UVSS patients and healthy donors. The analysis of differentially methylated positions and regions revealed a CS-specific epigenetic signature, enriched in developmental transcription factors, transmembrane transporters, and cell adhesion factors. The CS-specific signature compared to DNAm changes in other progeroid diseases and regular ageing, identifyied commonalities and differences in epigenetic remodelling. CS shares DNAm changes with normal ageing more than other progeroid diseases do, and according to the methylation clock CS samples show up to 13-fold accelerated ageing. Thus, CS is characterized by a specific epigenomic signature that partially overlaps with and exacerbates DNAm changes occurring in physiological aging. Our results unveil new genes and pathways that are potentially relevant for the progeroid/degenerative CS phenotype.

  7. 7

    المصدر: Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual)
    Universidade de São Paulo (USP)
    instacron:USP

    الوصف: Nucleotide excision repair (NER) is a conserved, flexible mechanism responsible for the removal of bulky, helix-distorting DNA lesions, like ultraviolet damage or cisplatin adducts, but its role in the repair of lesions generated by oxidative stress is still not clear. The helicase XPD/ERCC2, one of the two helicases of the transcription complex IIH, together with XPB, participates both in NER and in RNA pol II-driven transcription. In this work, we investigated the responses of distinct XPD-mutated cell lines to the oxidative stress generated by photoactivated methylene blue (MB) and KBrO3 treatments. The studied cells are derived from patients with XPD mutations but expressing different clinical phenotypes, including xeroderma pigmentosum (XP), XP and Cockayne syndrome (XP-D/CS) and trichothiodystrophy (TTD). We show by different approaches that all XPD-mutated cell lines tested were sensitive to oxidative stress, with those from TTD patients being the most sensitive. Host cell reactivation (HCR) assays showed that XP-D/CS and TTD cells have severely impaired repair capacity of oxidised lesions in plasmid DNA, and alkaline comet assays demonstrated the induction of significantly higher amounts of DNA strand breaks after treatment with photoactivated MB in these cells compared to wild-type cells. All XPD-mutated cells presented strong S/G2 arrest and persistent γ-H2AX staining after photoactivated MB treatment. Taken together, these results indicate that XPD participates in the repair of lesions induced by the redox process, and that XPD mutations lead to differences in the response to oxidatively induced damage.

  8. 8

    المساهمون: Laboratory Medicine, AGEM - Endocrinology, metabolism and nutrition, AGEM - Inborn errors of metabolism, Amsterdam Neuroscience - Cellular & Molecular Mechanisms, Amsterdam Reproduction & Development (AR&D), Molecular Genetics, Pathology, Laboratory Genetic Metabolic Diseases, AGEM - Amsterdam Gastroenterology Endocrinology Metabolism

    المصدر: American journal of human genetics, 105(2), 434-440. Cell Press
    The American Journal of Human Genetics
    American Journal of Human Genetics, 105(2), 434-440. Cell Press
    Theil, A F, Botta, E, Raams, A, Smith, D E C, Mendes, M I, Caligiuri, G, Giachetti, S, Bione, S, Carriero, R, Liberi, G, Zardoni, L, Swagemakers, S M A, Salomons, G S, Sarasin, A, Lehmann, A, van der Spek, P J, Ogi, T, Hoeijmakers, J H J, Vermeulen, W & Orioli, D 2019, ' Bi-allelic TARS Mutations Are Associated with Brittle Hair Phenotype ', American journal of human genetics, vol. 105, no. 2, pp. 434-440 . https://doi.org/10.1016/j.ajhg.2019.06.017Test

    الوصف: Brittle and “tiger-tail” hair is the diagnostic hallmark of trichothiodystrophy (TTD), a rare recessive disease associated with a wide spectrum of clinical features including ichthyosis, intellectual disability, decreased fertility, and short stature. As a result of premature abrogation of terminal differentiation, the hair is brittle and fragile and contains reduced cysteine content. Hypersensitivity to UV light is found in about half of individuals with TTD; all of these individuals harbor bi-allelic mutations in components of the basal transcription factor TFIIH, and these mutations lead to impaired nucleotide excision repair and basal transcription. Different genes have been found to be associated with non-photosensitive TTD (NPS-TTD); these include MPLKIP (also called TTDN1), GTF2E2 (also called TFIIEβ), and RNF113A. However, a relatively large group of these individuals with NPS-TTD have remained genetically uncharacterized. Here we present the identification of an NPS-TTD-associated gene, threonyl-tRNA synthetase (TARS), found by next-generation sequencing of a group of uncharacterized individuals with NPS-TTD. One individual has compound heterozygous TARS variants, c.826A>G (p.Lys276Glu) and c.1912C>T (p.Arg638∗), whereas a second individual is homozygous for the TARS variant: c.680T>C (p.Leu227Pro). We showed that these variants have a profound effect on TARS protein stability and enzymatic function. Our results expand the spectrum of genes involved in TTD to include genes implicated in amino acid charging of tRNA, which is required for the last step in gene expression, namely protein translation. We previously proposed that some of the TTD-specific features derive from subtle transcription defects as a consequence of unstable transcription factors. We now extend the definition of TTD from a transcription syndrome to a “gene-expression” syndrome.

  9. 9

    المصدر: American Journal of Medical Genetics Part A. 173:2511-2516

    الوصف: We describe the characterization of Xeroderma Pigmentosum variant (XPV) in a young Caucasian patient with phototype I, who exhibited a high sensitivity to sunburn and multiple cutaneous tumors at the age of 15 years. Two novel mutations in the POLH gene, which encodes the translesion DNA polymerase η, with loss of function due to two independent exon skippings, are reported to be associated as a compound heterozygous state in the patient. Western blot analysis performed on proteins from dermal fibroblasts derived from the patient and analysis of the mutation spectrum on immunoglobulin genes produced during the somatic hypermutation process in his memory B cells, show the total absence of translesion polymerase η activity in the patient. The total lack of Polη activity, necessary to bypass in an error-free manner UVR-induced pyrimidine dimers following sun exposure, explains the early unusual clinical appearance of this patient.

  10. 10

    المساهمون: Génomes et cancer (GC (FRE2939)), Université Paris-Sud - Paris 11 (UP11)-Institut Gustave Roussy (IGR)-Centre National de la Recherche Scientifique (CNRS), Genetique et Biotherapies des Maladies Degeneratives et Proliferatives du Systeme Nerveux (Inserm U745), Institut des sciences du Médicament -Toxicologie - Chimie - Environnement (IFR71), Institut National de la Santé et de la Recherche Médicale (INSERM)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Paris Descartes - Paris 5 (UPD5)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Bourgogne (UB), Fondation Jean Dausset CEPH, Laboratory of Hematology, Gustave Roussy, Villejuif, Praxiling (Praxiling), Centre National de la Recherche Scientifique (CNRS)-Université Paul-Valéry - Montpellier 3 (UPVM), Plateforme de Bioinformatique [Gustave Roussy], Analyse moléculaire, modélisation et imagerie de la maladie cancéreuse (AMMICa), Université Paris-Sud - Paris 11 (UP11)-Institut Gustave Roussy (IGR)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Institut Gustave Roussy (IGR)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Hématopoïèse normale et pathologique (U1170 Inserm), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Paris-Sud - Paris 11 (UP11)-Institut Gustave Roussy (IGR), Institut Cochin (IC UM3 (UMR 8104 / U1016)), Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Institut Necker Enfants-Malades (INEM - UM 111 (UMR 8253 / U1151)), Service de Dermatologie et Allergologie [CHRU Nancy], Centre Hospitalier Régional Universitaire de Nancy (CHRU Nancy), Service de génétique médicale, Université de Bordeaux (UB)-CHU Bordeaux [Bordeaux]-Groupe hospitalier Pellegrin, Universidade de Sao Paulo, Institute of Biomedical Sciences, Universidade de São Paulo (USP)-Institute of Biomedical Sciences (ICB/USP), Universidade de São Paulo (USP), Stabilité Génétique et Oncogenèse (UMR 8200), Hematopoïèse et Cellules Souches (U362), Institut Gustave Roussy (IGR)-Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpital Saint-Louis, Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Université Paris Diderot - Paris 7 (UPD7), Service d'hématologie et immunologie pédiatrique, Université Paris Diderot - Paris 7 (UPD7)-Hôpital Robert Debré-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP), Institut Gustave Roussy (IGR), Radiothérapie moléculaire (UMR 1030), Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut Gustave Roussy (IGR)-Université Paris-Sud - Paris 11 (UP11), 3UMR728 INSERM Unité d'immuno-hématologie (UIH) and laboratoire d'hématologie, Hôpital St-Louis, AP-HP, Centre National de la Recherche Scientifique (CNRS), Unité d'Hémato-Immunologie pédiatrique [Hôpital Robert Debré, Paris], Service d'Immuno-hématologie pédiatrique [Hôpital Robert Debré, Paris], Hôpital Robert Debré-Hôpital Robert Debré, Institut National de la Santé et de la Recherche Médicale (INSERM)-Ecole Nationale Supérieure de Chimie de Paris- Chimie ParisTech-PSL (ENSCP)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Ecole Nationale Supérieure de Chimie de Paris- Chimie ParisTech-PSL (ENSCP)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Paris Descartes - Paris 5 (UPD5)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM), Praxiling UMR 5267 (Praxiling), Université Paul-Valéry - Montpellier 3 (UM3)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut Gustave Roussy (IGR)-Institut National de la Santé et de la Recherche Médicale (INSERM), Université Paris Diderot - Paris 7 (UPD7)-Assistance publique - Hôpitaux de Paris (AP-HP) (APHP), Université Paris Diderot - Paris 7 (UPD7)-Hôpital Robert Debré-Assistance publique - Hôpitaux de Paris (AP-HP) (APHP)

    المصدر: Blood
    Blood, American Society of Hematology, 2019, 133 (25), pp.2718-2724. ⟨10.1182/blood-2019-01-895698⟩

    الوصف: There is a Blood Commentary on this article in this issue.