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1.
Biochem J ; 479(23): 2395-2417, 2022 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-36383217

RESUMO

The cancer-associated Epstein-Barr virus (EBV) latently infects and immortalises B lymphocytes. EBV latent membrane protein 2A and EBV-encoded microRNAs are known to manipulate B cell receptor signalling to control cell growth and survival and suppress lytic replication. Here, we show that the EBV transcription factors EBNA2, 3A, 3B and 3C bind to genomic sites around multiple B cell receptor (BCR) pathway genes, regulate their expression and affect BCR signalling. EBNA2 regulates the majority of BCR pathway genes associated with binding sites, where EBNA3 proteins regulate only 42% of targets predicted by binding. Both EBNA2 and 3 proteins predominantly repress BCR pathway gene expression and target some common genes. EBNA2 and at least one EBNA3 protein repress the central BCR components CD79A and CD79B and the downstream genes BLNK, CD22, CD72, NFATC1, PIK3CG and RASGRP3. Studying repression of CD79B, we show that EBNA2 decreases transcription by disrupting binding of Early B cell Factor-1 to the CD79B promoter. Consistent with repression of BCR signalling, we demonstrate that EBNA2 and EBNA3 proteins suppress the basal or active BCR signalling that culminates in NFAT activation. Additionally, we show that EBNA2, EBNA3A and EBNA3C expression can result in reductions in the active serine 473 phosphorylated form of Akt in certain cell contexts, consistent with transcriptional repression of the PI3K-Akt BCR signalling arm. Overall, we identify EBNA2, EBNA3A and EBNA3C-mediated transcription control of BCR signalling as an additional strategy through which EBV may control the growth and survival of infected B cells and maintain viral latency.


Assuntos
Infecções por Vírus Epstein-Barr , Antígenos Nucleares do Vírus Epstein-Barr , Humanos , Antígenos Nucleares do Vírus Epstein-Barr/genética , Herpesvirus Humano 4/genética , Infecções por Vírus Epstein-Barr/genética , Fosfatidilinositol 3-Quinases , Receptores de Antígenos de Linfócitos B/genética
2.
Br J Cancer ; 118(5): 727-732, 2018 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-29438375

RESUMO

BACKGROUND: Colorectal cancer (CRC) screening might be improved by using a measure of prior risk to modulate screening intensity or the faecal immunochemical test threshold. Intermediate molecular biomarkers could aid risk prediction by capturing both known and unknown risk factors. METHODS: We sampled normal bowel mucosa from the proximal colon, distal colon and rectum of 317 individuals undergoing colonoscopy. We defined cases as having a personal history of colorectal polyp(s)/cancer, and controls as having no history of colorectal neoplasia. Molecular analyses were performed for: telomere length (TL); global methylation; and the expression of genes in molecular pathways associated with colorectal tumourigenesis. We also calculated a polygenic risk score (PRS) based on CRC susceptibility polymorphisms. RESULTS: Bowel TL was significantly longer in cases than controls, but was not associated with blood TL. PRS was significantly and independently higher in cases. Hypermethylation showed a suggestive association with case:control status. No gene or pathway was differentially expressed between cases and controls. Gene expression often varied considerably between bowel locations. CONCLUSIONS: PRS and bowel TL (but not blood TL) may be clinically-useful predictors of CRC risk. Sample collection to assess these biomarkers is feasible in clinical practice, especially where population screening uses flexible sigmoidoscopy or colonoscopy.


Assuntos
Biomarcadores Tumorais/genética , Colo/química , Neoplasias Colorretais/diagnóstico , Reto/química , Homeostase do Telômero , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Colonoscopia , Neoplasias Colorretais/genética , Metilação de DNA , Detecção Precoce de Câncer , Feminino , Redes Reguladoras de Genes , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Fatores de Risco , Adulto Jovem
3.
Br J Cancer ; 118(12): 1683, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29780161

RESUMO

Since the publication of this paper, the authors noticed that James E. East was assigned to the incorrect affiliation. The affiliation information is provided correctly, above.

4.
Nucleic Acids Res ; 44(10): 4636-50, 2016 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-26883634

RESUMO

In B cells infected by the cancer-associated Epstein-Barr virus (EBV), RUNX3 and RUNX1 transcription is manipulated to control cell growth. The EBV-encoded EBNA2 transcription factor (TF) activates RUNX3 transcription leading to RUNX3-mediated repression of the RUNX1 promoter and the relief of RUNX1-directed growth repression. We show that EBNA2 activates RUNX3 through a specific element within a -97 kb super-enhancer in a manner dependent on the expression of the Notch DNA-binding partner RBP-J. We also reveal that the EBV TFs EBNA3B and EBNA3C contribute to RUNX3 activation in EBV-infected cells by targeting the same element. Uncovering a counter-regulatory feed-forward step, we demonstrate EBNA2 activation of a RUNX1 super-enhancer (-139 to -250 kb) that results in low-level RUNX1 expression in cells refractory to RUNX1-mediated growth inhibition. EBNA2 activation of the RUNX1 super-enhancer is also dependent on RBP-J. Consistent with the context-dependent roles of EBNA3B and EBNA3C as activators or repressors, we find that these proteins negatively regulate the RUNX1 super-enhancer, curbing EBNA2 activation. Taken together our results reveal cell-type-specific exploitation of RUNX gene super-enhancers by multiple EBV TFs via the Notch pathway to fine tune RUNX3 and RUNX1 expression and manipulate B-cell growth.


Assuntos
Linfócitos B/virologia , Subunidades alfa de Fatores de Ligação ao Core/genética , Elementos Facilitadores Genéticos , Antígenos Nucleares do Vírus Epstein-Barr/metabolismo , Fatores de Transcrição/metabolismo , Ativação Transcricional , Linfócitos B/metabolismo , Linhagem Celular , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Subunidade alfa 3 de Fator de Ligação ao Core/genética , Humanos , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina/metabolismo , Receptores Notch/metabolismo
5.
J Drugs Dermatol ; 15(9): 1116-20, 2016 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-27602975

RESUMO

BACKGROUND: Poly-ureaurethane has been previously described for the management of dry, brittle, and in general, dystrophic nails. The polymer yields a waterproof, breathable barrier to protect the nail plate and prevent further damage to the nail, while regulating transonychial water loss (TOWL). Because nail dystrophy and dessication are contributing factors to onychomycosis, a barrier that protects the nail but also allows a topical antifungal to permeate its shield is potentially an advantageous combination. Oral antifungals such as terbinafine, itraconazole, and fluconazole, as well as the newer topical antifungals efinaconazole and tavaborole (although formulated to penetrate the nail unit and work with the porosity and inherent electrical charge of the nail plate), do not take into account nail damage that has been created from years of harboring a dermatophyte infection. Up to 50% of cases presumed to be onychomycosis are in fact onychodystrophy without fungal infection, and laboratory testing for fungus should be obtained prior to initiating antifungal treatment. Whether a nail has onychomycosis, or onychodystrophy due to other causes, barrier function and structural integrity are compromised in diseased nails, and should be addressed. A poly-ureaurethane barrier that protects against wetting/drying, fungal reservoirs, and microtrauma, followed by the addition of oral or topical antifungals after laboratory fungal confirmation may optimize outcomes in the treatment of onychomycosis.
OBJECTIVE: The purpose of this work was to determine through in vitro release testing (IVRT) whether poly-ureaurethane 16% allows for penetration of efinaconazole 10% or tavaborole 5%. Results could spur subsequent clinical studies which would have implications for the addition of an antifungal based on fungal confirmation, after addresssing the underlying nail dystrophy primarily.
METHODS: A vertical diffusion cell system was used to evaluate the ability of efinaconazole 10% and tavaborole 5% to penetrate across poly-ureaurethane 16%. The diffusion cells had a 1.0 cm2 surface area and approximately 8 mL receptor volume. Poly-ureaurethane 16% was applied to a 0.45 μm nylon membrane and allowed to dry before use. Efinaconazole 10% or tavaborole 5% was then applied to the poly-ureaurethane 16% coated membrane, and samples were pulled from the receptor chamber at various times. Reverse phase chromatography was then used to assess the penetration of each active ingredient across the membrane.
RESULTS: The flux and permeability of efinaconazole or tavaborole across poly-ureaurethane 16% were determined from efinaconazole 10% or tavaborole 5%, respectively. The flux and permeability of efinaconazole were determined to be 503.9 +/- 31.9 μg/cm2/hr and 14.0 +/- 0.9 nm/sec. The flux and permeability of tavaborole were determined to be 755.5 +/- 290.4 μg/cm2/hr and 42.0 +/- 16.1 nm/sec.
CONCLUSION: In addition to the treatment of onychoschizia, onychorrhexis, and other signs of severe dessication of the nail plate, a barrier that regulates TOWL should be considered in the management onychomycosis to address barrier dysfunction and to promote stabilization of the damaged nail. Previously published flux values across the nail are reported to be 1.4 μg/cm2/day for efinaconazole and 204 μg/cm2/day for tavaborole. These values are substantially lower than the herein determined flux for both molecules across poly-ureaurethane 16%. A comparison of the data suggests that poly-ureaurethane 16%, if used prior to efinaconazole or tavaborole, would not limit the ability of either active ingredient to access the nail, and therefore, would be unlikely to reduce their antifungal effect. Onychodystrophy is inherent in, and often precedes onychomycosis, and consideration should be given for initiation of treatment in the same sequence: stabilizing and protecting the nail plate barrier primarily, and subsequently adding oral or topical antifungals after laboratory confirmation. Future clinical studies will be needed to determine combination efficacy for in vivo use.

J Drugs Dermatol. 2016;15(9):1116-1120.


Assuntos
Compostos de Boro/metabolismo , Compostos Bicíclicos Heterocíclicos com Pontes/metabolismo , Doenças da Unha , Unhas Malformadas , Onicomicose , Polímeros/metabolismo , Poliuretanos/metabolismo , Triazóis/metabolismo , Administração Tópica , Antifúngicos/administração & dosagem , Antifúngicos/química , Antifúngicos/metabolismo , Compostos de Boro/administração & dosagem , Compostos de Boro/química , Compostos Bicíclicos Heterocíclicos com Pontes/administração & dosagem , Compostos Bicíclicos Heterocíclicos com Pontes/química , Cultura em Câmaras de Difusão , Composição de Medicamentos , Humanos , Doenças da Unha/tratamento farmacológico , Doenças da Unha/metabolismo , Unhas Malformadas/tratamento farmacológico , Unhas Malformadas/metabolismo , Onicomicose/tratamento farmacológico , Onicomicose/metabolismo , Permeabilidade/efeitos dos fármacos , Polímeros/administração & dosagem , Polímeros/química , Poliuretanos/administração & dosagem , Poliuretanos/química , Triazóis/administração & dosagem , Triazóis/química
6.
J Virol ; 88(16): 8743-53, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24850736

RESUMO

UNLABELLED: Sequence differences in the EBNA-2 protein mediate the superior ability of type 1 Epstein-Barr virus (EBV) to transform human B cells into lymphoblastoid cell lines compared to that of type 2 EBV. Here we show that changing a single amino acid (S442D) from serine in type 2 EBNA-2 to the aspartate found in type 1 EBNA-2 confers a type 1 growth phenotype in a lymphoblastoid cell line growth maintenance assay. This amino acid lies in the transactivation domain of EBNA-2, and the S442D change increases activity in a transactivation domain assay. The superior growth properties of type 1 EBNA-2 correlate with the greater induction of EBV LMP-1 and about 10 cell genes, including CXCR7. In chromatin immunoprecipitation assays, type 1 EBNA-2 is shown to associate more strongly with EBNA-2 binding sites near the LMP-1 and CXCR7 genes. Unbiased motif searching of the EBNA-2 binding regions of the differentially regulated cell genes identified an ETS-interferon regulatory factor composite element motif that closely corresponds to the sequences known to mediate EBNA-2 regulation of the LMP-1 promoter. It appears that the superior induction by type 1 EBNA-2 of the cell genes contributing to cell growth is due to their being regulated in a manner different from that for most EBNA-2-responsive genes and in a way similar to that for the LMP-1 gene. IMPORTANCE: The EBNA-2 transcription factor plays a key role in B cell transformation by EBV and defines the two EBV types. Here we identify a single amino acid (Ser in type 1 EBV, Asp in type 2 EBV) of EBNA-2 that determines the superior ability of type 1 EBNA-2 to induce a key group of cell genes and the EBV LMP-1 gene, which mediate the growth advantage of B cells infected with type 1 EBV. The EBNA-2 binding sites in these cell genes have a sequence motif similar to the sequence known to mediate regulation of the EBV LMP-1 promoter. Further detailed analysis of transactivation and promoter binding provides new insight into the physiological regulation of cell genes by EBNA-2.


Assuntos
Aminoácidos/metabolismo , Linfócitos B/metabolismo , Linfócitos B/virologia , Antígenos Nucleares do Vírus Epstein-Barr/metabolismo , Proteínas Virais/metabolismo , Aminoácidos/genética , Ácido Aspártico/genética , Ácido Aspártico/metabolismo , Sítios de Ligação/genética , Linhagem Celular , Imunoprecipitação da Cromatina/métodos , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Antígenos Nucleares do Vírus Epstein-Barr/genética , Genes Virais/genética , Células HEK293 , Humanos , Regiões Promotoras Genéticas/genética , Receptores CXCR/genética , Receptores CXCR/metabolismo , Serina/genética , Serina/metabolismo , Ativação Transcricional/genética , Proteínas da Matriz Viral/genética , Proteínas da Matriz Viral/metabolismo , Proteínas Virais/genética
7.
PLoS Pathog ; 9(9): e1003636, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24068937

RESUMO

Epstein-Barr virus (EBV) epigenetically reprogrammes B-lymphocytes to drive immortalization and facilitate viral persistence. Host-cell transcription is perturbed principally through the actions of EBV EBNA 2, 3A, 3B and 3C, with cellular genes deregulated by specific combinations of these EBNAs through unknown mechanisms. Comparing human genome binding by these viral transcription factors, we discovered that 25% of binding sites were shared by EBNA 2 and the EBNA 3s and were located predominantly in enhancers. Moreover, 80% of potential EBNA 3A, 3B or 3C target genes were also targeted by EBNA 2, implicating extensive interplay between EBNA 2 and 3 proteins in cellular reprogramming. Investigating shared enhancer sites neighbouring two new targets (WEE1 and CTBP2) we discovered that EBNA 3 proteins repress transcription by modulating enhancer-promoter loop formation to establish repressive chromatin hubs or prevent assembly of active hubs. Re-ChIP analysis revealed that EBNA 2 and 3 proteins do not bind simultaneously at shared sites but compete for binding thereby modulating enhancer-promoter interactions. At an EBNA 3-only intergenic enhancer site between ADAM28 and ADAMDEC1 EBNA 3C was also able to independently direct epigenetic repression of both genes through enhancer-promoter looping. Significantly, studying shared or unique EBNA 3 binding sites at WEE1, CTBP2, ITGAL (LFA-1 alpha chain), BCL2L11 (Bim) and the ADAMs, we also discovered that different sets of EBNA 3 proteins bind regulatory elements in a gene and cell-type specific manner. Binding profiles correlated with the effects of individual EBNA 3 proteins on the expression of these genes, providing a molecular basis for the targeting of different sets of cellular genes by the EBNA 3s. Our results therefore highlight the influence of the genomic and cellular context in determining the specificity of gene deregulation by EBV and provide a paradigm for host-cell reprogramming through modulation of enhancer-promoter interactions by viral transcription factors.


Assuntos
Reprogramação Celular , Elementos Facilitadores Genéticos , Antígenos Nucleares do Vírus Epstein-Barr/metabolismo , Marcação de Genes , Herpesvirus Humano 4/metabolismo , Modelos Biológicos , Proteínas Repressoras/metabolismo , Oxirredutases do Álcool/química , Oxirredutases do Álcool/genética , Oxirredutases do Álcool/metabolismo , Sítios de Ligação , Ligação Competitiva , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular , Proteínas Correpressoras , Infecções por Vírus Epstein-Barr/metabolismo , Infecções por Vírus Epstein-Barr/patologia , Antígenos Nucleares do Vírus Epstein-Barr/química , Antígenos Nucleares do Vírus Epstein-Barr/genética , Interações Hospedeiro-Patógeno , Humanos , Proteínas do Tecido Nervoso/química , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Proteínas Nucleares/química , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas Tirosina Quinases/química , Proteínas Tirosina Quinases/genética , Proteínas Tirosina Quinases/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Proteínas Repressoras/química , Proteínas Repressoras/genética , Proteínas Virais/química , Proteínas Virais/genética , Proteínas Virais/metabolismo
8.
J Virol ; 86(9): 5165-78, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22357270

RESUMO

Epstein-Barr virus (EBV) establishes a persistent latent infection in B lymphocytes and is associated with the development of numerous human tumors. Epstein-Barr nuclear antigen 3C (EBNA 3C) is essential for B-cell immortalization, has potent cell cycle deregulation capabilities, and functions as a regulator of both viral- and cellular-gene expression. We performed transcription profiling on EBNA 3C-expressing B cells and identified several chemokines and members of integrin receptor-signaling pathways, including CCL3, CCL4, CXCL10, CXCL11, ITGA4, ITGB1, ADAM28, and ADAMDEC1, as cellular target genes that could be repressed by the action of EBNA 3C alone. Chemotaxis assays demonstrated that downregulation of CXCL10 and -11 by EBNA 3C is sufficient to reduce the migration of cells expressing the CXCL10 and -11 receptor CXCR3. Gene repression by EBNA 3C was accompanied by decreased histone H3 lysine 9/14 acetylation and increased histone H3 lysine 27 trimethylation. In an EBV-positive cell line expressing all latent genes, we identified binding sites for EBNA 3C at ITGB1 and ITGA4 and in a distal regulatory region between ADAMDEC1 and ADAM28, providing the first demonstration of EBNA 3C association with cellular-gene control regions. Our data implicate indirect mechanisms in CXCL10 and CXCL11 repression by EBNA 3C. In summary, we have unveiled key cellular pathways repressed by EBNA 3C that are likely to contribute to the ability of EBV-immortalized cells to modulate immune responses, adhesion, and B-lymphocyte migration to facilitate persistence in the host.


Assuntos
Antígenos Virais/metabolismo , Regulação para Baixo/genética , Integrinas/genética , Regiões Promotoras Genéticas , Transdução de Sinais , Proteínas ADAM/genética , Animais , Sítios de Ligação , Adesão Celular/genética , Linhagem Celular , Inibição de Migração Celular/genética , Quimiocinas/genética , Quimiotaxia/genética , Antígenos Nucleares do Vírus Epstein-Barr , Regulação da Expressão Gênica , Humanos , Camundongos , Receptores CXCR3/metabolismo , Elementos Reguladores de Transcrição
9.
Methods Mol Biol ; 2633: 87-95, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36853459

RESUMO

Site-Directed Mutagenesis (SDM) allows for changes in the DNA sequence of plasmids using polymerase chain reaction (PCR). It is a reliable, accessible, and rapid method which is the common initial step of many biochemial or genetic experiments. Here we describe the various different forms of SDM before giving a detailed method for the introduction of substitutions, insertions, or deletions using a fast, ligation-free protocol, followed by colony PCR to screen for mutated sequences.


Assuntos
Mutagênese Sítio-Dirigida , Reação em Cadeia da Polimerase
10.
Acta Crystallogr Sect E Struct Rep Online ; 68(Pt 9): m1158-9, 2012 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-22969458

RESUMO

The title compound, [Mo(C(5)H(5))(C(2)H(3)O)(C(13)H(13)P)(CO)(2)], was prepared by reaction of [Mo(CH(3))(C(5)H(5))(CO)(3)] with methyl-diphenyl-phosphane. The Mo(II) atom exhibits a four-legged piano-stool coordination geometry with the acetyl and phosphane ligands trans to each other. There are several inter-molecular C-H⋯O hydrogen-bonding inter-actions involving carbonyl and acetyl O atoms as acceptors. A close nearly parallel π-π inter-action between the cyclo-penta-dienyl plane and the phenyl ring of the phosphane ligand is present, with an angle of 6.4 (1)° between the two least-squares planes. The centroid-to-centroid distance between these groups is 3.772 (3) Å, and the closest distance between two atoms of these groups is 3.449 (4) Å. Since each Mo complex is engaged in two of these inter-actions, the complexes form an infinite π-stack coincident with the a axis.

11.
Psychol Serv ; 19(2): 294-304, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-33539135

RESUMO

Veterans face a variety of stressors due to their military service and are more likely to develop psychological problems as a result. Research suggests that as many as half of veterans with mental health conditions go untreated due to barriers including lack of accessibility to services and stigma. The present study builds on previous research by using meta-analytic techniques to determine the effectiveness of telepsychology-delivered therapy with veterans. Empirical studies were included if they reported veteran-related outcome data on a psychological intervention used to treat a mental health condition remotely using either videoconferencing or telephone. Twenty-seven studies including 2,648 total participants (1,667 in treatment conditions and 981 in control conditions) met our inclusion criteria and were incorporated into our analysis. Twenty-five studies provided pre-post data to evaluate various therapy outcomes, and 18 studies used a randomized clinical trials (RCTs) design that allowed a comparison between telehealth and traditional in-person therapy. Publication bias was evaluated using correlations between sample and effect sizes for posttraumatic stress disorder (PTSD) and depression for pretest-posttest and RCT designs; risk was determined to be minimal. Weighted average pre-post effect sizes were moderate-to-strong for depression and trauma, and videoconferencing was more effective than telephone for depression (d = 0.86 and 0.46, respectively) and trauma (d = 1.00 and 0.51, respectively). Weighted average effect sizes computed from RCT studies suggest telepsychology is similarly effective as services provided face-to-face. More research is needed for telepsychology-delivered treatments for other mental health conditions faced by veterans. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Assuntos
Transtornos de Estresse Pós-Traumáticos , Telemedicina , Veteranos , Humanos , Transtornos de Estresse Pós-Traumáticos/terapia , Telemedicina/métodos , Telefone , Comunicação por Videoconferência
12.
Nat Commun ; 10(1): 30, 2019 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-30604745

RESUMO

The inactive X chromosome (Xi) in female mammals adopts an atypical higher-order chromatin structure, manifested as a global loss of local topologically associated domains (TADs), A/B compartments and formation of two mega-domains. Here we demonstrate that the non-canonical SMC family protein, SmcHD1, which is important for gene silencing on Xi, contributes to this unique chromosome architecture. Specifically, allelic mapping of the transcriptome and epigenome in SmcHD1 mutant cells reveals the appearance of sub-megabase domains defined by gene activation, CpG hypermethylation and depletion of Polycomb-mediated H3K27me3. These domains, which correlate with sites of SmcHD1 enrichment on Xi in wild-type cells, additionally adopt features of active X chromosome higher-order chromosome architecture, including A/B compartments and partial restoration of TAD boundaries. Xi chromosome architecture changes also occurred following SmcHD1 knockout in a somatic cell model, but in this case, independent of Xi gene derepression. We conclude that SmcHD1 is a key factor in defining the unique chromosome architecture of Xi.


Assuntos
Proteínas Cromossômicas não Histona/genética , Metilação de DNA/genética , Ativação Transcricional/genética , Inativação do Cromossomo X , Alelos , Animais , Sistemas CRISPR-Cas , Linhagem Celular , Proteínas Cromossômicas não Histona/metabolismo , Ilhas de CpG , Éxons/genética , Feminino , Fibroblastos , Técnicas de Inativação de Genes , Histonas/genética , Histonas/metabolismo , Masculino , Camundongos , Mutação Puntual , Proteínas do Grupo Polycomb/metabolismo
13.
DNA Repair (Amst) ; 62: 1-7, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29223032

RESUMO

Transitions of cytosine to thymine in CpG dinucleotides are the most frequent type of mutations observed in cancer. This increased mutability is commonly explained by the presence of 5-methylcytosine (5mC) and its spontaneous hydrolytic deamination into thymine. Here, we describe observations that question whether spontaneous deamination alone causes the elevated mutagenicity of 5mC. Tumours with somatic mutations in DNA mismatch-repair genes or in the proofreading domain of DNA polymerase ε (Pol ε) exhibit more 5mC to T transitions than would be expected, given the kinetics of hydrolytic deamination. This enrichment is asymmetrical around replication origins with a preference for the leading strand template, in particular in methylated cytosines flanked by guanines (GCG). Notably, GCG to GTG mutations also exhibit strand asymmetry in mismatch-repair and Pol ε wild-type tumours. Together, these findings suggest that mis-incorporation of A opposite 5mC during replication of the leading strand might be a contributing factor in the mutagenesis of methylated cytosine.


Assuntos
5-Metilcitosina/metabolismo , Reparo de Erro de Pareamento de DNA , DNA Polimerase II/metabolismo , Replicação do DNA , Mutagênese , Neoplasias/genética , Carcinogênese , Ilhas de CpG , Humanos , Neoplasias/enzimologia , Neoplasias/metabolismo
14.
Cell Rep ; 20(10): 2313-2327, 2017 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-28877467

RESUMO

Chromatin modifications and the promoter-associated epigenome are important for the regulation of gene expression. However, the mechanisms by which chromatin-modifying complexes are targeted to the appropriate gene promoters in vertebrates and how they influence gene expression have remained poorly defined. Here, using a combination of live-cell imaging and functional genomics, we discover that the vertebrate SET1 complex is targeted to actively transcribed gene promoters through CFP1, which engages in a form of multivalent chromatin reading that involves recognition of non-methylated DNA and histone H3 lysine 4 trimethylation (H3K4me3). CFP1 defines SET1 complex occupancy on chromatin, and its multivalent interactions are required for the SET1 complex to place H3K4me3. In the absence of CFP1, gene expression is perturbed, suggesting that normal targeting and function of the SET1 complex are central to creating an appropriately functioning vertebrate promoter-associated epigenome.


Assuntos
Ilhas de CpG/genética , Histonas/metabolismo , Animais , Cromatina/metabolismo , Imunoprecipitação da Cromatina , Metilação de DNA/genética , Recuperação de Fluorescência Após Fotodegradação , Humanos , Metilação , Regiões Promotoras Genéticas/genética , Espectrometria de Fluorescência
15.
Elife ; 52016 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-27183007

RESUMO

CpG dinucleotides are the main mutational hot-spot in most cancers. The characteristic elevated C>T mutation rate in CpG sites has been related to 5-methylcytosine (5mC), an epigenetically modified base which resides in CpGs and plays a role in transcription silencing. In brain nearly a third of 5mCs have recently been found to exist in the form of 5-hydroxymethylcytosine (5hmC), yet the effect of 5hmC on mutational processes is still poorly understood. Here we show that 5hmC is associated with an up to 53% decrease in the frequency of C>T mutations in a CpG context compared to 5mC. Tissue specific 5hmC patterns in brain, kidney and blood correlate with lower regional CpG>T mutation frequency in cancers originating in the respective tissues. Together our data reveal global and opposing effects of the two most common cytosine modifications on the frequency of cancer causing somatic mutations in different cell types.


Assuntos
5-Metilcitosina/análogos & derivados , Neoplasias Encefálicas/genética , DNA de Neoplasias/genética , Epigênese Genética , Neoplasias Renais/genética , Taxa de Mutação , Síndromes Mielodisplásicas/genética , 5-Metilcitosina/química , 5-Metilcitosina/metabolismo , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Ilhas de CpG , Metilação de DNA , DNA de Neoplasias/metabolismo , Bases de Dados Genéticas , Humanos , Neoplasias Renais/metabolismo , Neoplasias Renais/patologia , Síndromes Mielodisplásicas/metabolismo , Síndromes Mielodisplásicas/patologia , Células Mieloides/metabolismo , Células Mieloides/patologia , Sequenciamento do Exoma
17.
J Matern Fetal Neonatal Med ; 26(18): 1799-803, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23662746

RESUMO

OBJECTIVE: To determine if the addition of group education regarding maternal serum screening and diagnostic testing for aneuploidy and neural tube defects improves patient knowledge and affects the uptake of testing compared to individual education alone. METHOD: We conducted a prospective study of 443 obstetric patients to assess knowledge of prenatal testing options based on individual provider counseling (n = 331) or provider counseling with supplemental group education (n = 112). We used a chi-square test to compare the number of correct survey answers between the two groups. RESULTS: There was no difference in baseline knowledge. Patients receiving group education showed a statistically significant improvement in knowledge. After initiation of group education, the uptake of maternal serum screening declined while the uptake of amniocentesis remained unchanged. CONCLUSION: Group education in addition to individual counseling to discuss prenatal testing options appears to be effective in improving knowledge compared to individual provider counseling alone. Improved knowledge may affect uptake of prenatal screening tests due to more informed decision making.


Assuntos
Conhecimento , Educação de Pacientes como Assunto/métodos , Diagnóstico Pré-Natal , Adulto , Aneuploidia , Tomada de Decisões , Síndrome de Down/diagnóstico , Feminino , Aconselhamento Genético , Humanos , Defeitos do Tubo Neural/diagnóstico , Grupo Associado , Gravidez , Diagnóstico Pré-Natal/métodos , Diagnóstico Pré-Natal/estatística & dados numéricos , Adulto Jovem
18.
Psychol Serv ; 9(3): 272-292, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22867120

RESUMO

Using technology as a service medium has been touted as a potentially feasible and effective alternative and/or adjunct to in-person services. The telepsychology literature has given less attention to children and adolescents in comparison to adults. This review provides a summary and critique of the empirical research focused on psychological services provided to children and adolescents using three technology media (i.e., videoconferencing, Internet, and telephone). The evidentiary support for providing services with each of these media for a range of concerns is encouraging. The quantity and quality of research, however, both need to be enhanced to better understand how technology mediates the provision of youth services, as well as to elevate telepsychology within professional psychology. Future research and its subsequent impact on policy and practice are considered.


Assuntos
Transtornos Mentais/terapia , Psicoterapia/métodos , Telemedicina/métodos , Adolescente , Criança , Humanos
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