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[PMID]:26782556
[Au] Autor:Tomiyama MP; Werle CH; Milanez GP; Nóbrega DB; Pereira JP; Calarga AP; Flores F; Brocchi M
[Ad] Endereço:Departamento de Genética, Evolução e Bioagentes, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, Brasil.
[Ti] Título:Salmonella enterica Typhimurium fljBA operon stability: implications regarding the origin of Salmonella enterica I 4,[5],12:i:.
[So] Source:Genet Mol Res;14(4):19057-65, 2015 Dec 29.
[Is] ISSN:1676-5680
[Cp] País de publicação:Brazil
[La] Idioma:eng
[Ab] Resumo:Salmonella enterica subsp enterica serovar 4,5,12:i:- has been responsible for many recent Salmonella outbreaks worldwide. Several studies indicate that this serovar originated from S. enterica subsp enterica serovar Typhimurium, by the loss of the flagellar phase II gene (fljB) and adjacent sequences. However, at least two different clones of S. enterica 4,5,12:i:- exist that differs in the molecular events responsible for fljB deletion. The aim of this study was to test the stability of the fljBA operon responsible for the flagellar phase variation under different growth conditions in order to verify if its deletion is a frequent event that could explain the origin and dissemination of this serovar. In fact, coding sequences for transposons are present near this operon and in some strains, such as S. enterica Typhimurium LT2, the Fels-2 prophage gene is inserted near this operon. The presence of mobile DNA could confer instability to this region. In order to examine this, the cat (chloramphenicol acetyltransferase) gene was inserted adjacent to the fljBA operon so that deletions involving this genomic region could be identified. After growing S. enterica chloramphenicol-resistant strains under different conditions, more than 104 colonies were tested for the loss of chloramphenicol resistance. However, none of the colonies were sensitive to chloramphenicol. These data suggest that the origin of S. enterica serovar 4,5,12:i:- from Typhimurium by fljBA deletion is not a frequent event. The origin and dissemination of 4,5,12:i:- raise several questions about the role of flagellar phase variation in virulence.
[Mh] Termos MeSH primário: Óperon
Salmonella typhimurium/genética
[Mh] Termos MeSH secundário: Animais
Antibacterianos/farmacologia
Sequência de DNA Instável
DNA Bacteriano/genética
Farmacorresistência Bacteriana/genética
Evolução Molecular
Feminino
Genes Bacterianos
Camundongos Endogâmicos BALB C
Testes de Sensibilidade Microbiana
Mitomicina/farmacologia
Infecções por Salmonella/microbiologia
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Anti-Bacterial Agents); 0 (DNA, Bacterial); 50SG953SK6 (Mitomycin)
[Em] Mês de entrada:1610
[Cu] Atualização por classe:161230
[Lr] Data última revisão:
161230
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160120
[St] Status:MEDLINE
[do] DOI:10.4238/2015.December.29.13


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[PMID]:26384951
[Au] Autor:Guo P; Lam SL
[Ad] Endereço:Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
[Ti] Título:New insights into the genetic instability in CCTG repeats.
[So] Source:FEBS Lett;589(20 Pt B):3058-63, 2015 Oct 07.
[Is] ISSN:1873-3468
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Tetranucleotide CCTG repeat expansion is associated with myotonic dystrophy type 2, which is an inherited and progressive muscle degeneration disease. Yet, no cure is available and the molecular mechanism of repeat expansion remains elusive. In this study, we used high-resolution nuclear magnetic resonance spectroscopy to reveal a mini-dumbbell structure formed by two CCTG repeats. Upon slippage in the nascent strand during DNA replication, the formation of the mini-dumbbell provides a possible pathway for a two-repeat expansion. In addition, fast exchange between two competing mini-dumbbells among three repeats results in a mini-loop structure that accounts for one-repeat expansion. These mini-dumbbell and mini-loop intermediates can also co-exist at multiple sites in CCTG repeats, leading to three or larger size repeat expansions.
[Mh] Termos MeSH primário: Sequência de DNA Instável
DNA/química
Conformação de Ácido Nucleico
Sequências Repetitivas de Ácido Nucleico
[Mh] Termos MeSH secundário: Sequência de Bases
DNA/genética
Expansão das Repetições de DNA
Seres Humanos
Espectroscopia de Ressonância Magnética/métodos
Modelos Moleculares
Distrofia Miotônica/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
9007-49-2 (DNA)
[Em] Mês de entrada:1601
[Cu] Atualização por classe:151005
[Lr] Data última revisão:
151005
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150920
[St] Status:MEDLINE


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[PMID]:26225720
[Au] Autor:Sproviero M; Verwey AM; Witham AA; Manderville RA; Sharma P; Wetmore SD
[Ad] Endereço:†Department of Chemistry and Toxicology, University of Guelph, Guelph, ON Canada N1G 2W1.
[Ti] Título:Enhancing Bulge Stabilization through Linear Extension of C8-Aryl-Guanine Adducts to Promote Polymerase Blockage or Strand Realignment to Produce a C:C Mismatch.
[So] Source:Chem Res Toxicol;28(8):1647-58, 2015 Aug 17.
[Is] ISSN:1520-5010
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Aryl radicals can react at the C8-site of 2'-deoxyguanosine (dG) to produce DNA adducts with a C8-C linkage (denoted C-linked). Such adducts are structurally distinct from those possessing a flexible amine (N-linked) or ether (O-linked) linkage, which separates the C8-aryl moiety from the guanine nucleobase. In the current study, two model C-linked C8-dG adducts, namely, C8-benzo[b]thienyl-dG ([BTh]G) and C8-(pyren-1-yl)-dG ([Py]G), were incorporated into the NarI (12mer, NarI(12) and 22mer, NarI(22)) hotspot sequence for frameshift mutations in bacteria. For the first time, C-linked C8-dG adducts are shown to stabilize the -2 deletion duplex within the NarI sequence. Primer-elongation assays employing Sulfolobus solfataricus P2 DNA polymerase IV (Dpo4) demonstrates the influence of C8-aryl ring size and shape in promoting Dpo4 blockage or strand realignment to produce a C:C mismatch downstream of the adduct site. Molecular dynamics simulations of the -2 deletion duplex suggest that both anti and syn adduct structures are energetically accessible. These findings provide a rationale for describing the biochemical outcome induced by C-linked C8-dG adducts when processed by Dpo4.
[Mh] Termos MeSH primário: Pareamento Incorreto de Bases
Adutos de DNA/química
DNA Polimerase Dirigida por DNA/metabolismo
Guanina/química
[Mh] Termos MeSH secundário: Sequência de DNA Instável
Estabilidade Enzimática
Alinhamento de Sequência
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (DNA Adducts); 5Z93L87A1R (Guanine); EC 2.7.7.7 (DNA-Directed DNA Polymerase)
[Em] Mês de entrada:1606
[Cu] Atualização por classe:150817
[Lr] Data última revisão:
150817
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150731
[St] Status:MEDLINE
[do] DOI:10.1021/acs.chemrestox.5b00233


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[PMID]:24854722
[Au] Autor:Manjari SR; Pata JD; Banavali NK
[Ad] Endereço:Laboratory of Computational and Structural Biology, Division of Genetics, Biggs Laboratory, Wadsworth Center, New York State Department of Health , Empire State Plaza, PO Box 509 , Albany, New York 12201-0509, United States.
[Ti] Título:Cytosine unstacking and strand slippage at an insertion-deletion mutation sequence in an overhang-containing DNA duplex.
[So] Source:Biochemistry;53(23):3807-16, 2014 Jun 17.
[Is] ISSN:1520-4995
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Base unstacking in template strands, when accompanied by strand slippage, can result in deletion mutations during strand extension by nucleic acid polymerases. In a GCCC mutation hot-spot sequence, which was previously identified to have a 50% probability of causing such mutations during DNA replication by a Y-family polymerase, a single-base deletion mutation could result from such unstacking of any one of its three template cytosines. In this study, the intrinsic energetic differences in unstacking among these three cytosines in a solvated DNA duplex overhang model were examined using umbrella sampling molecular dynamics simulations. The free energy profiles obtained show that cytosine unstacking grows progressively more unfavorable as one moves inside the duplex from the 5'-end of the overhang template strand. Spontaneous strand slippage occurs in response to such base unstacking in the direction of both the major and minor grooves for all three cytosines. Unrestrained simulations run from three distinct strand-slipped states and one non-strand-slipped state suggest that a more duplexlike environment can help stabilize strand slippage. The possible underlying reasons and biological implications of these observations are discussed in the context of nucleic acid replication active site dynamics.
[Mh] Termos MeSH primário: Citosina/química
DNA/química
Deleção de Genes
Modelos Moleculares
Mutagênese Insercional
[Mh] Termos MeSH secundário: Proteínas Arqueais/química
Proteínas Arqueais/genética
Proteínas Arqueais/metabolismo
Citosina/metabolismo
DNA/metabolismo
Replicação do DNA
Sequência de DNA Instável
DNA Polimerase Dirigida por DNA/química
DNA Polimerase Dirigida por DNA/genética
DNA Polimerase Dirigida por DNA/metabolismo
Simulação de Dinâmica Molecular
Método de Monte Carlo
Proteínas Mutantes/química
Proteínas Mutantes/metabolismo
Conformação de Ácido Nucleico
Sulfolobus acidocaldarius/enzimologia
[Pt] Tipo de publicação:COMPARATIVE STUDY; JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Archaeal Proteins); 0 (Mutant Proteins); 8J337D1HZY (Cytosine); 9007-49-2 (DNA); EC 2.7.7.7 (DNA-Directed DNA Polymerase)
[Em] Mês de entrada:1409
[Cu] Atualização por classe:170220
[Lr] Data última revisão:
170220
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:140524
[St] Status:MEDLINE
[do] DOI:10.1021/bi500189g


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[PMID]:23829161
[Au] Autor:Liang H; Severin N; Fugmann S; Sokolov IM; Rabe JP
[Ad] Endereço:Department of Physics, Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489 Berlin, Germany.
[Ti] Título:Statistics of time-dependent rupture of single ds-DNA.
[So] Source:J Phys Chem B;117(29):8875-9, 2013 Jul 25.
[Is] ISSN:1520-5207
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Double-stranded (ds-) DNA molecules were stretched and ruptured on molecularly modified graphite surfaces with a scanning force microscope (SFM) exerting a force parallel to the surface. The stretching force was either large enough to break the molecule immediately or compensated by the elastic restoring force of the DNA backbone, which stabilized the molecular length. However, the size-stabilized molecules broke gradually from longer molecules to shorter ones with time. The breakage of different lengths of stabilized molecules was recorded in order to study time-dependent mechanical properties of the molecules under constant forces. From these data, a relatively high rate constant, k0 = (2.2 ± 0.1) × 10(-7) s(-1), was calculated. Moreover, we found a nonlinear stress-strain dependence of DNA on the surface which we attributed to DNA conformational transition. Assuming that the structural transition on the surface is similar to that in solution we estimated the forces needed to stretch the molecules and thereby verify the estimation of the activation energy barrier.
[Mh] Termos MeSH primário: Sequência de DNA Instável
DNA/química
[Mh] Termos MeSH secundário: Microscopia Eletrônica de Varredura
Conformação Molecular
Estatística como Assunto
Fatores de Tempo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
9007-49-2 (DNA)
[Em] Mês de entrada:1402
[Cu] Atualização por classe:130725
[Lr] Data última revisão:
130725
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:130709
[St] Status:MEDLINE
[do] DOI:10.1021/jp400872k


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[PMID]:23267059
[Au] Autor:Jeffreys AJ; Cotton VE; Neumann R; Lam KW
[Ad] Endereço:Department of Genetics, University of Leicester, Leicester LE1 7RH, United Kingdom. ajj@le.ac.uk
[Ti] Título:Recombination regulator PRDM9 influences the instability of its own coding sequence in humans.
[So] Source:Proc Natl Acad Sci U S A;110(2):600-5, 2013 Jan 08.
[Is] ISSN:1091-6490
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:PRDM9 plays a key role in specifying meiotic recombination hotspot locations in humans and mice via recognition of hotspot sequence motifs by a variable tandem-repeat zinc finger domain in the protein. We now explore germ-line instability of this domain in humans. We show that repeat turnover is driven by mitotic and meiotic mutation pathways, the latter frequently resulting in substantial remodeling of zinc fingers. Turnover dynamics predict frequent allele switches in populations with correspondingly fast changes of the recombination landscape, fully consistent with the known rapid evolution of hotspot locations. We found variation in meiotic instability between men that correlated with PRDM9 status. One particular "destabilizer" variant caused hyperinstability not only of itself but also of otherwise-stable alleles in heterozygotes. PRDM9 protein thus appears to regulate the instability of its own coding sequence. However, destabilizer variants are strongly self-limiting in populations and probably have little impact on the evolution of the recombination landscape.
[Mh] Termos MeSH primário: Sequência de DNA Instável/genética
Evolução Molecular
Histona-Lisina N-Metiltransferase/genética
Recombinação Genética/genética
[Mh] Termos MeSH secundário: Fracionamento Químico
Simulação por Computador
Genética Populacional
Mutação em Linhagem Germinativa/genética
Seres Humanos
Funções Verossimilhança
Masculino
Repetições Minissatélites/genética
Taxa de Mutação
Oligonucleotídeos/genética
Análise de Sequência de DNA
Dedos de Zinco/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Oligonucleotides); EC 2.1.1.43 (Histone-Lysine N-Methyltransferase); EC 2.1.1.43 (PRDM9 protein, human)
[Em] Mês de entrada:1303
[Cu] Atualização por classe:170922
[Lr] Data última revisão:
170922
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:121226
[St] Status:MEDLINE
[do] DOI:10.1073/pnas.1220813110


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[PMID]:23248292
[Au] Autor:Arlow T; Scott K; Wagenseller A; Gammie A
[Ad] Endereço:Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
[Ti] Título:Proteasome inhibition rescues clinically significant unstable variants of the mismatch repair protein Msh2.
[So] Source:Proc Natl Acad Sci U S A;110(1):246-51, 2013 Jan 02.
[Is] ISSN:1091-6490
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:MSH2 is required for DNA mismatch repair recognition in eukaryotes. Deleterious mutations in human MSH2 account for approximately half of the alleles associated with a common hereditary cancer syndrome. Previously, we characterized clinically identified MSH2 missense mutations, using yeast as a model system, and found that the most common cause of defective DNA mismatch repair was low levels of the variant Msh2 proteins. Here, we show that increased protein turnover is responsible for the reduced cellular levels. Increasing gene dosage of more than half of the missense alleles fully restored function. A titration experiment revealed that raising the expression level of one variant to less than wild-type levels restored mismatch repair, suggesting that overexpression is not always required to regain function. We found that the ubiquitin-mediated proteasome degradation pathway is the major mechanism for increased turnover of the Msh2 variants and identified the primary ubiquitin ligase as San1. Deletion of San1 restored protein levels for all but one variant, but did not elevate wild-type Msh2 levels. The unstable variants interacted with San1, whereas wild-type Msh2 did not. Additionally, san1Δ suppressed the mismatch repair defect of unstable variants. Of medical significance, the clinically approved drug Bortezomib partially restored protein levels and mismatch repair function for low-level variants and reversed the resistance to cisplatin, a common chemotherapeutic. Our results provide the foundation for an innovative therapeutic regime for certain mismatch-repair-defective cancers that are refractory to conventional chemotherapies.
[Mh] Termos MeSH primário: Neoplasias Colorretais Hereditárias sem Polipose/genética
Regulação da Expressão Gênica/genética
Modelos Moleculares
Proteína 2 Homóloga a MutS/química
Complexo de Endopeptidases do Proteassoma/metabolismo
Proteínas de Saccharomyces cerevisiae/química
Proteínas de Saccharomyces cerevisiae/genética
Ubiquitina-Proteína Ligases/genética
[Mh] Termos MeSH secundário: Ácidos Borônicos/farmacologia
Bortezomib
Cisplatino
Neoplasias Colorretais Hereditárias sem Polipose/tratamento farmacológico
Reparo de Erro de Pareamento de DNA/efeitos dos fármacos
Reparo de Erro de Pareamento de DNA/genética
Primers do DNA/genética
Sequência de DNA Instável/genética
Dosagem de Genes/genética
Seres Humanos
Immunoblotting
Imuno-Histoquímica
Imunoprecipitação
Proteína 2 Homóloga a MutS/genética
Mutação de Sentido Incorreto/genética
Plasmídeos/genética
Reação em Cadeia da Polimerase
Pirazinas/farmacologia
Saccharomyces cerevisiae
Ubiquitina
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Boronic Acids); 0 (DNA Primers); 0 (Pyrazines); 0 (Saccharomyces cerevisiae Proteins); 0 (Ubiquitin); 69G8BD63PP (Bortezomib); EC 2.3.2.27 (SAN1 protein, S cerevisiae); EC 2.3.2.27 (Ubiquitin-Protein Ligases); EC 3.4.25.1 (Proteasome Endopeptidase Complex); EC 3.6.1.3 (MSH2 protein, S cerevisiae); EC 3.6.1.3 (MSH2 protein, human); EC 3.6.1.3 (MutS Homolog 2 Protein); Q20Q21Q62J (Cisplatin)
[Em] Mês de entrada:1302
[Cu] Atualização por classe:161215
[Lr] Data última revisão:
161215
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:121219
[St] Status:MEDLINE
[do] DOI:10.1073/pnas.1215510110


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[PMID]:23009001
[Au] Autor:Cichosz G; Wiackowski SK
[Ad] Endereço:University of Warmia and Mazury on Olsztyn, Poland.
[Ti] Título:[Genetically modified food--great unknown].
[Ti] Título:Zywnosc genetycznie modyfikowana--wielka niewiadoma..
[So] Source:Pol Merkur Lekarski;33(194):59-63, 2012 Aug.
[Is] ISSN:1426-9686
[Cp] País de publicação:Poland
[La] Idioma:pol
[Ab] Resumo:Genetically modified food (GMF) creates evident threat to consumers' health. In spite of assurances of biotechnologists, DNA of transgenic plants is instable, so, synthesis of foreign, allergenic proteins is possible. Due to high trypsin inhibitor content the GMF is digested much more slowly what, alike Bt toxin presence, increases probability of alimentary canal diseases. Next threats are bound to the presence of fitoestrogens and residues of Roundup pesticide, that can diminish reproductiveness; and even lead to cancerogenic transformation through disturbance of human hormonal metabolism. In spite of food producers and distributors assurances that food made of GMF raw materials is marked, de facto consumers have no choice. Moreover, along the food law products containing less than 0.9% of GMF protein are not included into genetically modified food.
[Mh] Termos MeSH primário: Doenças do Sistema Digestório/induzido quimicamente
Alimentos Geneticamente Modificados/toxicidade
Doenças Transmitidas por Alimentos/etiologia
[Mh] Termos MeSH secundário: Transformação Celular Neoplásica/induzido quimicamente
Sequência de DNA Instável
Análise de Alimentos
Seres Humanos
Fitoestrógenos/efeitos adversos
Fitoestrógenos/análise
Plantas Geneticamente Modificadas/genética
[Pt] Tipo de publicação:EDITORIAL; ENGLISH ABSTRACT
[Nm] Nome de substância:
0 (Phytoestrogens)
[Em] Mês de entrada:1210
[Cu] Atualização por classe:120926
[Lr] Data última revisão:
120926
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:120927
[St] Status:MEDLINE


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[PMID]:20931230
[Au] Autor:Molina O; Anton E; Vidal F; Blanco J
[Ad] Endereço:Unitat de Biologia Cel·lular, Facultat de Biociències, Universitat Autònoma de Barcelona, 08193, Bellaterra (Cerdanyola del Vallès), Spain.
[Ti] Título:Sperm rates of 7q11.23, 15q11q13 and 22q11.2 deletions and duplications: a FISH approach.
[So] Source:Hum Genet;129(1):35-44, 2011 Jan.
[Is] ISSN:1432-1203
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:Genomic disorders are human diseases caused by meiotic chromosomal rearrangements of unstable regions flanked by Low Copy Repeats (LCRs). LCRs act as substrates for Non-Allelic Homologous Recombination (NAHR) leading to deletions and duplications. The aim of this study was to assess the basal frequency of deletions and duplications of the 7q11.23, 15q11-q13 and 22q11.2 regions in spermatozoa from control donors to check differences in the susceptibility to generate anomalies and to assess the contribution of intra- and inter-chromatid NAHR events. Semen samples from ten control donors were processed by FISH. A customized combination of probes was used to discriminate among normal, deleted and duplicated sperm genotypes. A minimum of 10,000 sperm were assessed per sample and region. There were no differences in the mean frequency of deletions and duplications (del + dup) among the 7q11.23, 15q11-q13 and 22q11.2 regions (frequency ± SEM, 0.37 ± 0.02; 0.46 ± 0.07 and 0.27 ± 0.07%, respectively) (P = 0.122). Nevertheless, hierarchical cluster analysis reveals interindividual differences suggesting that particular haplotypes could be the main source of variability in NAHR rates. The mean frequency of deletions was not different from the mean frequency of duplications in the 7q11.23 (P = 0.202) and 15q11-q13 (P = 0.609) regions, indicating a predominant inter-chromatid NAHR. By contrast, in the 22q11.2 region the frequency of deletions slightly exceed duplications (P = 0.032), although at the individual level any donor showed differences. Altogether, our results support the inter-chromatid NAHR as the predominant mechanism involved in the generation of sperm deletions and duplications.
[Mh] Termos MeSH primário: Aberrações Cromossômicas
Cromossomos Humanos Par 15/genética
Cromossomos Humanos Par 22/genética
Cromossomos Humanos Par 7/genética
Deleção de Genes
Duplicação Gênica
Espermatozoides
Doadores de Tecidos
[Mh] Termos MeSH secundário: Adulto
Cromátides/genética
Sequência de DNA Instável/genética
Haplótipos/genética
Seres Humanos
Hibridização in Situ Fluorescente
Masculino
Meia-Idade
Recombinação Genética
Duplicações Segmentares Genômicas/genética
Adulto Jovem
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1102
[Cu] Atualização por classe:171007
[Lr] Data última revisão:
171007
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:101009
[St] Status:MEDLINE
[do] DOI:10.1007/s00439-010-0894-4


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[PMID]:20843782
[Au] Autor:Rindler PM; Bidichandani SI
[Ad] Endereço:Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
[Ti] Título:Role of transcript and interplay between transcription and replication in triplet-repeat instability in mammalian cells.
[So] Source:Nucleic Acids Res;39(2):526-35, 2011 Jan.
[Is] ISSN:1362-4962
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Triplet-repeat expansions cause several inherited human diseases. Expanded triplet-repeats are unstable in somatic cells, and tissue-specific somatic instability contributes to disease pathogenesis. In mammalian cells instability of triplet-repeats is dependent on the location of the origin of replication relative to the repeat tract, supporting the 'fork-shift' model of repeat instability. Disease-causing triplet-repeats are transcribed, but how this influences instability remains unclear. We examined instability of the expanded (GAA•TTC)(n) sequence in mammalian cells by analyzing individual replication events directed by the SV40 origin from five different locations, in the presence and absence of doxycycline-induced transcription. Depending on the location of the SV40 origin, either no instability was observed, instability was caused by replication with no further increase due to transcription, or instability required transcription. Whereas contractions accounted for most of the observed instability, one construct showed expansions upon induction of transcription. These expansions disappeared when transcript stability was reduced via removal or mutation of a spliceable intron. These results reveal a complex interrelationship of transcription and replication in the etiology of repeat instability. While both processes may not be sufficient for the initiation of instability, transcription and/or transcript stability seem to further modulate the fork-shift model of triplet-repeat instability.
[Mh] Termos MeSH primário: Replicação do DNA
Sequência de DNA Instável
Transcrição Genética
Repetições de Trinucleotídeos
[Mh] Termos MeSH secundário: Animais
Células COS
Cercopithecus aethiops
Estabilidade de RNA
RNA Mensageiro/metabolismo
Origem de Replicação
Vírus 40 dos Símios/genética
Expansão das Repetições de Trinucleotídeos
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (RNA, Messenger)
[Em] Mês de entrada:1103
[Cu] Atualização por classe:161122
[Lr] Data última revisão:
161122
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:100917
[St] Status:MEDLINE
[do] DOI:10.1093/nar/gkq788



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