54 research outputs found

    CHD1 Remodels Chromatin and Influences Transient DNA Methylation at the Clock Gene frequency

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    Circadian-regulated gene expression is predominantly controlled by a transcriptional negative feedback loop, and it is evident that chromatin modifications and chromatin remodeling are integral to this process in eukaryotes. We previously determined that multiple ATP–dependent chromatin-remodeling enzymes function at frequency (frq). In this report, we demonstrate that the Neurospora homologue of chd1 is required for normal remodeling of chromatin at frq and is required for normal frq expression and sustained rhythmicity. Surprisingly, our studies of CHD1 also revealed that DNA sequences within the frq promoter are methylated, and deletion of chd1 results in expansion of this methylated domain. DNA methylation of the frq locus is altered in strains bearing mutations in a variety of circadian clock genes, including frq, frh, wc-1, and the gene encoding the frq antisense transcript (qrf). Furthermore, frq methylation depends on the DNA methyltransferase, DIM-2. Phenotypic characterization of Δdim-2 strains revealed an approximate WT period length and a phase advance of approximately 2 hours, indicating that methylation plays only an ancillary role in clock-regulated gene expression. This suggests that DNA methylation, like the antisense transcript, is necessary to establish proper clock phasing but does not control overt rhythmicity. These data demonstrate that the epigenetic state of clock genes is dependent on normal regulation of clock components

    Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

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    We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012

    Molecular Characterization of Podoviral Bacteriophages Virulent for Clostridium perfringens and Their Comparison with Members of the Picovirinae

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    Clostridium perfringens is a Gram-positive, spore-forming anaerobic bacterium responsible for human food-borne disease as well as non-food-borne human, animal and poultry diseases. Because bacteriophages or their gene products could be applied to control bacterial diseases in a species-specific manner, they are potential important alternatives to antibiotics. Consequently, poultry intestinal material, soil, sewage and poultry processing drainage water were screened for virulent bacteriophages that lysed C. perfringens. Two bacteriophages, designated ΦCPV4 and ΦZP2, were isolated in the Moscow Region of the Russian Federation while another closely related virus, named ΦCP7R, was isolated in the southeastern USA. The viruses were identified as members of the order Caudovirales in the family Podoviridae with short, non-contractile tails of the C1 morphotype. The genomes of the three bacteriophages were 17.972, 18.078 and 18.397 kbp respectively; encoding twenty-six to twenty-eight ORF's with inverted terminal repeats and an average GC content of 34.6%. Structural proteins identified by mass spectrometry in the purified ΦCP7R virion included a pre-neck/appendage with putative lyase activity, major head, tail, connector/upper collar, lower collar and a structural protein with putative lysozyme-peptidase activity. All three podoviral bacteriophage genomes encoded a predicted N-acetylmuramoyl-L-alanine amidase and a putative stage V sporulation protein. Each putative amidase contained a predicted bacterial SH3 domain at the C-terminal end of the protein, presumably involved with binding the C. perfringens cell wall. The predicted DNA polymerase type B protein sequences were closely related to other members of the Podoviridae including Bacillus phage Φ29. Whole-genome comparisons supported this relationship, but also indicated that the Russian and USA viruses may be unique members of the sub-family Picovirinae

    Italian guidelines for primary headaches: 2012 revised version

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    The first edition of the Italian diagnostic and therapeutic guidelines for primary headaches in adults was published in J Headache Pain 2(Suppl. 1):105–190 (2001). Ten years later, the guideline committee of the Italian Society for the Study of Headaches (SISC) decided it was time to update therapeutic guidelines. A literature search was carried out on Medline database, and all articles on primary headache treatments in English, German, French and Italian published from February 2001 to December 2011 were taken into account. Only randomized controlled trials (RCT) and meta-analyses were analysed for each drug. If RCT were lacking, open studies and case series were also examined. According to the previous edition, four levels of recommendation were defined on the basis of levels of evidence, scientific strength of evidence and clinical effectiveness. Recommendations for symptomatic and prophylactic treatment of migraine and cluster headache were therefore revised with respect to previous 2001 guidelines and a section was dedicated to non-pharmacological treatment. This article reports a summary of the revised version published in extenso in an Italian version

    Consensus Paper: The Role of the Cerebellum in Perceptual Processes

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    Homozygous deletion of the UGT2B17 gene is not associated with osteoporosis risk in elderly Caucasian women

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    SUMMARY: Previously, homozygous deletion of the UGT2B17 gene has shown association with hip fracture. Using a high-throughput qRT-PCR assay, we genotyped UGT2B17 copy number variation (CNV) in 1,347 elderly Caucasian women and examined for effects on bone phenotypes. We found no evidence of association between UGT2B17 CNV and osteoporosis risk in this population. INTRODUCTION: Genetic studies of osteoporosis commonly examine SNPs in candidate genes or whole genome analyses, but insertions and deletions of DNA, collectively called CNV, also comprise a large amount of the genetic variability between individuals. Previously, homozygous deletion of the UGT2B17 gene in CNV 4q13.2, which encodes an enzyme that mediates the glucuronidation of steroid hormones, has shown association with the risk of hip fracture. METHODS: We used a quantitative real-time PCR assay for genotyping the UGT2B17 CNV in a well-characterized population study of 1,347 Caucasian women aged 75.2 ± 2.7 (mean ± SD) years, to assess the effect of the CNV on bone mass density (BMD) at the total hip site and osteoporosis risk. RESULTS: The UGT2B17 CNV distribution was consistent with the expected Hardy-Weinberg distribution and not different from frequencies previously reported in a Caucasian population. Data from ANCOVA of age- and weight-adjusted BMD for UGT2B17 CNV genotype showed no significant difference between genotype groups. Individuals with homozygous or heterozygous deletion of the UGT2B17 gene showed no increased risk of incident fragility fracture. CONCLUSIONS: These data suggest that quantitative real-time PCR is a rapid and efficient technique for determination of candidate CNVs, including the UGT2B17 CNV; however, we found no evidence of an effect of UGT2B17 CNV on osteoporosis risk in elderly Caucasian women
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