243 research outputs found

    Perturbation with Intrabodies Reveals That Calpain Cleavage Is Required for Degradation of Huntingtin Exon 1

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    Background: Proteolytic processing of mutant huntingtin (mHtt), the protein that causes Huntington's disease (HD), is critical for mHtt toxicity and disease progression. mHtt contains several caspase and calpain cleavage sites that generate N-terminal fragments that are more toxic than full-length mHtt. Further processing is then required for the degradation of these fragments, which in turn, reduces toxicity. This unknown, secondary degradative process represents a promising therapeutic target for HD. Methodology/Principal Findings: We have used intrabodies, intracellularly expressed antibody fragments, to gain insight into the mechanism of mutant huntingtin exon 1 (mHDx-1) clearance. Happ1, an intrabody recognizing the proline-rich region of mHDx-1, reduces the level of soluble mHDx-1 by increasing clearance. While proteasome and macroautophagy inhibitors reduce turnover of mHDx-1, Happ1 is still able to reduce mHDx-1 under these conditions, indicating Happ1-accelerated mHDx-1 clearance does not rely on these processes. In contrast, a calpain inhibitor or an inhibitor of lysosomal pH block Happ1-mediated acceleration of mHDx-1 clearance. These results suggest that mHDx-1 is cleaved by calpain, likely followed by lysosomal degradation and this process regulates the turnover rate of mHDx-1. Sequence analysis identifies amino acid (AA) 15 as a potential calpain cleavage site. Calpain cleavage of recombinant mHDx-1 in vitro yields fragments of sizes corresponding to this prediction. Moreover, when the site is blocked by binding of another intrabody, V_L12.3, turnover of soluble mHDx-1 in living cells is blocked. Conclusions/Significance: These results indicate that calpain-mediated removal of the 15 N-terminal AAs is required for the degradation of mHDx-1, a finding that may have therapeutic implications

    Planejamento estrat?gico organizacional : reflex?es a partir da utiliza??o das matrizes SWOT e GUT em uma associa??o de catadores de materiais recicl?veis.

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    O trabalho teve como objetivo aplicar as matrizes SWOT e GUT na Associa??o de Materiais Recicl?veis do Munic?pio de Jo?o Monlevade- MG para analisar sua situa??o atual e estabelecer prioridades em rela??o aos principais problemas levantados, de modo a servir de insumos para a constru??o de um planejamento estrat?gico. Para tanto, utilizou-se as matrizes SWOT e GUT, que s?o ferramentas que promovem o diagn?stico do ambiente organizacional, priorizando algumas a??es estrat?gicas que ampliam a possibilidade de sucesso da organiza??o, tanto no presente como no futuro. Quanto aos procedimentos metodol?gicos, o estudo fundamenta-se em pesquisas bibliogr?ficas e documentais, pesquisa-a??o, acompanhamento das atividades di?rias da associa??o, participa??o nas reuni?es internas e externas dos associados e/ou parceiros da organiza??o, di?logo com os catadores, acompanhamento e an?lise do programa da coleta seletiva implantada. Observa-se que a aplica??o das matrizes SWOT e GUT colabora para o reconhecimento de caracter?sticas que inviabilizam a sustentabilidade, produtividade, fideliza??o dos clientes, vantagem competitiva, entre outras, t?o importantes quanto as destacadas. O resultado da pesquisa apresenta fatores que auxiliaram na edifica??o de novas fases e a??es de curto, m?dio e/ou longo prazo na associa??o, de modo a tentar garantir sucesso e sustentabilidade

    A Rapid FACS-Based Strategy to Isolate Human Gene Knockin and Knockout Clones

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    Gene targeting protocols for mammalian cells remain inefficient and labor intensive. Here we describe FASTarget, a rapid, fluorescent cell sorting based strategy to isolate rare gene targeting events in human somatic cells. A fluorescent protein is used as a means for direct selection of targeted clones obviating the need for selection and outgrowth of drug resistant clones. Importantly, the use of a promoter-less, ATG-less construct greatly facilitates the recovery of correctly targeted cells. Using this method we report successful gene targeting in up to 94% of recovered human somatic cell clones. We create functional EYFP-tagged knockin clones in both transformed and non-transformed human somatic cell lines providing a valuable tool for mammalian cell biology. We further demonstrate the use of this technology to create gene knockouts. Using this generally applicable strategy we can recover gene targeted clones within approximately one month from DNA construct delivery to obtaining targeted monoclonal cell lines

    Perinatal factors associated with developmental defects of enamel in primary teeth: a case-control study

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    The present study was designed to evaluate associations between developmental defects of enamel (DDE) in the primary dentition and aspects related to mothers and preschoolers in the city of Diamantina, Brazil. A case-control study was carried out involving children aged three to fve years. The case group was composed of 104 children with at least one dental surface affected by DDE. The control group comprised 105 children without DDE, matched for gender and age. The diagnosis of enamel defects was performed using the Developmental Defects of Enamel Index. Information was collected through interviews investigating socio-demographic aspects, gestation, birth weight, prematurity and breastfeeding. Simple and multiple regression analyses were performed, providing unadjusted and adjusted prevalence ratios (Poisson regression). DDE were more prevalent among children who had not been breastfed (PR =?1.57; 95% CI: 1.1?2.2) and those whose mothers were under 24 years of age at the birth of the child (PR =?1.41; 95% CI: 1.1?1.9). The prevalence of DDE in the primary dentition was higher among children who had not been breastfed and those whose mothers were under 24 years of age at the birth of the child

    Milk intake and incident stroke and CHD in populations of European descent: a Mendelian randomisation study.

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    Higher milk intake has been associated with a lower stroke risk, but not with risk of CHD. Residual confounding or reverse causation cannot be excluded. Therefore, we estimated the causal association of milk consumption with stroke and CHD risk through instrumental variable (IV) and gene-outcome analyses. IV analysis included 29 328 participants (4611 stroke; 9828 CHD) of the European Prospective Investigation into Cancer and Nutrition (EPIC)-CVD (eight European countries) and European Prospective Investigation into Cancer and Nutrition-Netherlands (EPIC-NL) case-cohort studies. rs4988235, a lactase persistence (LP) SNP which enables digestion of lactose in adulthood was used as genetic instrument. Intake of milk was first regressed on rs4988235 in a linear regression model. Next, associations of genetically predicted milk consumption with stroke and CHD were estimated using Prentice-weighted Cox regression. Gene-outcome analysis included 777 024 participants (50 804 cases) from MEGASTROKE (including EPIC-CVD), UK Biobank and EPIC-NL for stroke, and 483 966 participants (61 612 cases) from CARDIoGRAM, UK Biobank, EPIC-CVD and EPIC-NL for CHD. In IV analyses, each additional LP allele was associated with a higher intake of milk in EPIC-CVD (β = 13·7 g/d; 95 % CI 8·4, 19·1) and EPIC-NL (36·8 g/d; 95 % CI 20·0, 53·5). Genetically predicted milk intake was not associated with stroke (HR per 25 g/d 1·05; 95 % CI 0·94, 1·16) or CHD (1·02; 95 % CI 0·96, 1·08). In gene-outcome analyses, there was no association of rs4988235 with risk of stroke (OR 1·02; 95 % CI 0·99, 1·05) or CHD (OR 0·99; 95 % CI 0·95, 1·03). Current Mendelian randomisation analysis does not provide evidence for a causal inverse relationship between milk consumption and stroke or CHD risk

    Estimated substitution of tea or coffee for sugar-sweetened beverages was associated with lower type 2 diabetes incidence in case-cohort analysis across 8 European countries in the epic-interact study.

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    INTRODUCTION: Beverage consumption is a modifiable risk factor for type 2 diabetes (T2D), but there is insufficient evidence to inform the suitability of substituting 1 type of beverage for another. OBJECTIVE: The aim of this study was to estimate the risk of T2D when consumption of sugar-sweetened beverages (SSBs) was replaced with consumption of fruit juice, milk, coffee, or tea. METHODS: In the European Prospective Investigation into Cancer and Nutrition (EPIC)-InterAct case-cohort study of 8 European countries (n = 27,662, with 12,333 cases of incident T2D, 1992-2007), beverage consumption was estimated at baseline by dietary questionnaires. Using Prentice-weighted Cox regression adjusting for other beverages and potential confounders, we estimated associations of substituting 1 type of beverage for another on incident T2D. RESULTS: Mean ± SD of estimated consumption of SSB was 55 ± 105 g/d. Means ± SDs for the other beverages were as follows: fruit juice, 59 ± 101 g/d; milk, 209 ± 203 g/d; coffee, 381 ± 372 g/d; and tea, 152 ± 282 g/d. Substituting coffee for SSBs by 250 g/d was associated with a 21% lower incidence of T2D (95% CI: 12%, 29%). The rate difference was -12.0 (95% CI: -20.0, -5.0) per 10,000 person-years among adults consuming SSBs ≥250 g/d (absolute rate = 48.3/10,000). Substituting tea for SSBs was estimated to lower T2D incidence by 22% (95% CI: 15%, 28%) or -11.0 (95% CI: -20.0, -2.6) per 10,000 person-years, whereas substituting fruit juice or milk was estimated not to alter T2D risk significantly. CONCLUSIONS: These findings indicate a potential benefit of substituting coffee or tea for SSBs for the primary prevention of T2D and may help formulate public health recommendations on beverage consumption in different populations

    Quantitative Microscopy Reveals Centromeric Chromatin Stability, Size, and Cell Cycle Mechanisms to Maintain Centromere Homeostasis

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    The deposited item is a book chapter and is part of the series "Centromeres and Kinetochores" published by the publisher Springer Verlag. The deposited book chapter is a post-print version and has been submitted to peer reviewing. There is no public supplementary material available for this publication. This publication hasn't any creative commons license associated.Centromeres are chromatin domains specified by nucleosomes containing the histone H3 variant, CENP-A. This unique centromeric structure is at the heart of a strong self-templating epigenetic mechanism that renders centromeres heritable. We review how specific quantitative microscopy approaches have contributed to the determination of the copy number, architecture, size, and dynamics of centromeric chromatin and its associated centromere complex and kinetochore. These efforts revealed that the key to long-term centromere maintenance is the slow turnover of CENP-A nucleosomes, a critical size of the chromatin domain and its cell cycle-coupled replication. These features come together to maintain homeostasis of a chromatin locus that directs its own epigenetic inheritance and facilitates the assembly of the mitotic kinetochore.There are no funders and sponsors indicated explicitly in the document.info:eu-repo/semantics/publishedVersio
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