844 research outputs found

    PAX6 mutations: genotype-phenotype correlations

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    BACKGROUND: The PAX6 protein is a highly conserved transcriptional regulator that is important for normal ocular and neural development. In humans, heterozygous mutations of the PAX6 gene cause aniridia (absence of the iris) and related developmental eye diseases. PAX6 mutations are archived in the Human PAX6 Allelic Variant Database, which currently contains 309 records, 286 of which are mutations in patients with eye malformations. RESULTS: We examined the records in the Human PAX6 Allelic Variant Database and documented the frequency of different mutation types, the phenotypes associated with different mutation types, the contribution of CpG transitions to the PAX6 mutation spectrum, and the distribution of chain-terminating mutations in the open reading frame. Mutations that introduce a premature termination codon into the open reading frame are predominantly associated with aniridia; in contrast, non-aniridia phenotypes are typically associated with missense mutations. Four CpG dinucleotides in exons 8, 9, 10 and 11 are major mutation hotspots, and transitions at these CpG's account for over half of all nonsense mutations in the database. Truncating mutations are distributed throughout the PAX6 coding region, except for the last half of exon 12 and the coding part of exon 13, where they are completely absent. The absence of truncating mutations in the 3' part of the coding region is statistically significant and is consistent with the idea that nonsense-mediated decay acts on PAX6 mutant alleles. CONCLUSION: The PAX6 Allelic Variant Database is a valuable resource for studying genotype-phenotype correlations. The consistent association of truncating mutations with the aniridia phenotype, and the distribution of truncating mutations in the PAX6 open reading frame, suggests that nonsense-mediated decay acts on PAX6 mutant alleles

    BLM and RMI1 alleviate RPA inhibition of topoIIIα decatenase activity

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    RPA is a single-stranded DNA binding protein that physically associates with the BLM complex. RPA stimulates BLM helicase activity as well as the double Holliday junction dissolution activity of the BLM-topoisomerase IIIα complex. We investigated the effect of RPA on the ssDNA decatenase activity of topoisomerase IIIα. We found that RPA and other ssDNA binding proteins inhibit decatenation by topoisomerase IIIα. Complex formation between BLM, TopoIIIα, and RMI1 ablates inhibition of decatenation by ssDNA binding proteins. Together, these data indicate that inhibition by RPA does not involve species-specific interactions between RPA and BLM-TopoIIIα-RMI1, which contrasts with RPA modulation of double Holliday junction dissolution. We propose that topoisomerase IIIα and RPA compete to bind to single-stranded regions of catenanes. Interactions with BLM and RMI1 enhance toposiomerase IIIα activity, promoting decatenation in the presence of RPA

    Detection of weak gravitational lensing distortions of distant galaxies by cosmic dark matter at large scales

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    Most of the matter in the universe is not luminous and can be observed directly only through its gravitational effect. An emerging technique called weak gravitational lensing uses background galaxies to reveal the foreground dark matter distribution on large scales. Light from very distant galaxies travels to us through many intervening overdensities which gravitationally distort their apparent shapes. The observed ellipticity pattern of these distant galaxies thus encodes information about the large-scale structure of the universe, but attempts to measure this effect have been inconclusive due to systematic errors. We report the first detection of this ``cosmic shear'' using 145,000 background galaxies to reveal the dark matter distribution on angular scales up to half a degree in three separate lines of sight. The observed angular dependence of this effect is consistent with that predicted by two leading cosmological models, providing new and independent support for these models.Comment: 18 pages, 5 figures: To appear in Nature. (This replacement fixes tex errors and typos.

    The Costs and Benefits of Renewable Portfolio Standards in the United States: Accounting for Policy Heterogeneity and Endogeneity

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    Renewable portfolio standards (RPS) have emerged as some of the main state-level policy tools addressing climate change. The central aim of this thesis is to investigate the costs and benefits of these policies in terms of their impacts on the share of non-hydro renewables and electricity prices, respectively. To accurately estimate these impacts, this paper argues that it is necessary to account for policy heterogeneity (i.e., differences in policy features across states) and endogeneity (i.e., the correlation between policy features and unobservable factors that affect the dependent variables). In the literature, there has been work addressing the former, and there is a modest consensus that RPS is effective when heterogeneity is considered. However, there has been little work addressing endogeneity. To address this gap in the literature, this thesis uses the instrumental variable (IV) and control function (CF) approaches to account for endogeneity and measures of RPS that capture policy heterogeneity. It compares the results from these approaches with the results of baseline regressions that account for heterogeneity but not endogeneity. In the results for the non-hydro renewable share, RPS is found to have significant impacts in the baseline but not in the IV and CF regressions. However, the validity of the results in the IV regressions depends on the strength of the instrument, which varies considerably depending on whether the instrument is lagged or if year fixed effects are included. For electricity prices, the IV approach indicates that RPS has no significant impact, while the CF approach indicates there is a significant and positive impact that is higher in magnitude than in baseline and in the literature. Due to this inconsistency between the two approaches, as well as other limitations, this thesis ends by discussing whether the results are useful for public policy. It argues that the literature on RPS has not reached the point where strong conclusions can be made about the impact of these policies

    Accuracy and repeatability of wrist joint angles in boxing using an electromagnetic tracking system

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    © 2019, The Author(s). The hand-wrist region is reported as the most common injury site in boxing. Boxers are at risk due to the amount of wrist motions when impacting training equipment or their opponents, yet we know relatively little about these motions. This paper describes a new method for quantifying wrist motion in boxing using an electromagnetic tracking system. Surrogate testing procedure utilising a polyamide hand and forearm shape, and in vivo testing procedure utilising 29 elite boxers, were used to assess the accuracy and repeatability of the system. 2D kinematic analysis was used to calculate wrist angles using photogrammetry, whilst the data from the electromagnetic tracking system was processed with visual 3D software. The electromagnetic tracking system agreed with the video-based system (paired t tests) in both the surrogate ( 0.9). In the punch testing, for both repeated jab and hook shots, the electromagnetic tracking system showed good reliability (ICCs > 0.8) and substantial reliability (ICCs > 0.6) for flexion–extension and radial-ulnar deviation angles, respectively. The results indicate that wrist kinematics during punching activities can be measured using an electromagnetic tracking system

    Revealing the electroweak properties of a new scalar resonance

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    One or more new heavy resonances may be discovered in experiments at the CERN Large Hadron Collider. In order to determine if such a resonance is the long-awaited Higgs boson, it is essential to pin down its spin, CP, and electroweak quantum numbers. Here we describe how to determine what role a newly-discovered neutral CP-even scalar plays in electroweak symmetry breaking, by measuring its relative decay rates into pairs of electroweak vector bosons: WW, ZZ, \gamma\gamma, and Z\gamma. With the data-driven assumption that electroweak symmetry breaking respects a remnant custodial symmetry, we perform a general analysis with operators up to dimension five. Remarkably, only three pure cases and one nontrivial mixed case need to be disambiguated, which can always be done if all four decay modes to electroweak vector bosons can be observed or constrained. We exhibit interesting special cases of Higgs look-alikes with nonstandard decay patterns, including a very suppressed branching to WW or very enhanced branchings to \gamma\gamma and Z\gamma. Even if two vector boson branching fractions conform to Standard Model expectations for a Higgs doublet, measurements of the other two decay modes could unmask a Higgs imposter.Comment: 23 pages, two figures; v2: minor revision and version to appear in JHE

    Backbone resonance assignments of the monomeric DUF59 domain of human Fam96a

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    Proteins containing a domain of unknown function 59 (DUF59) appear to have a variety of physiological functions, ranging from iron-sulfur cluster assembly to DNA repair. DUF59 proteins have been found in bacteria, archaea and eukaryotes, however Fam96a and Fam96b are the only mammalian proteins predicted to contain a DUF59 domain. Fam96a is an 18 kDa protein comprised primarily of a DUF59 domain (residues 31-157) and an N-terminal signal peptide (residues 1-27). Interestingly, the DUF59 domain of Fam96a exists as monomeric and dimeric forms in solution, and X-ray crystallography studies of both forms unexpectedly revealed two different domain-swapped dimer structures. Here we report the backbone resonance assignments and secondary structure of the monomeric form of the 127 residue DUF59 domain of human Fam96a. This study provides the basis for further understanding the structural variability exhibited by Fam96a and the mechanism for domain swapping

    Replication of LDL SWAs hits in PROSPER/PHASE as validation for future (pharmaco)genetic analyses

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    <p><b>Background:</b> The PHArmacogenetic study of Statins in the Elderly at risk (PHASE) is a genome wide association study in the PROspective Study of Pravastatin in the Elderly at risk for vascular disease (PROSPER) that investigates the genetic variation responsible for the individual variation in drug response to pravastatin. Statins lower LDL-cholesterol in general by 30%, however not in all subjects. Moreover, clinical response is highly variable and adverse effects occur in a minority of patients. In this report we first describe the rationale of the PROSPER/PHASE project and second show that the PROSPER/PHASE study can be used to study pharmacogenetics in the elderly.</p> <p><b>Methods:</b> The genome wide association study (GWAS) was conducted using the Illumina 660K-Quad beadchips following manufacturer's instructions. After a stringent quality control 557,192 SNPs in 5,244 subjects were available for analysis. To maximize the availability of genetic data and coverage of the genome, imputation up to 2.5 million autosomal CEPH HapMap SNPs was performed with MACH imputation software. The GWAS for LDL-cholesterol is assessed with an additive linear regression model in PROBABEL software, adjusted for age, sex, and country of origin to account for population stratification.</p> <p><b>Results:</b> Forty-two SNPs reached the GWAS significant threshold of p = 5.0e-08 in 5 genomic loci (APOE/APOC1; LDLR; FADS2/FEN1; HMGCR; PSRC1/CELSR5). The top SNP (rs445925, chromosome 19) with a p-value of p = 2.8e-30 is located within the APOC1 gene and near the APOE gene. The second top SNP (rs6511720, chromosome 19) with a p-value of p = 5.22e-15 is located within the LDLR gene. All 5 genomic loci were previously associated with LDL-cholesterol levels, no novel loci were identified. Replication in WOSCOPS and CARE confirmed our results.</p> <p><b>Conclusion:</b> With the GWAS in the PROSPER/PHASE study we confirm the previously found genetic associations with LDL-cholesterol levels. With this proof-of-principle study we show that the PROSPER/PHASE study can be used to investigate genetic associations in a similar way to population based studies. The next step of the PROSPER/PHASE study is to identify the genetic variation responsible for the variation in LDL-cholesterol lowering in response to statin treatment in collaboration with other large trials.</p&gt
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