223 research outputs found

    Tankyrase 1 and Tankyrase 2 Are Essential but Redundant for Mouse Embryonic Development

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    Tankyrases are proteins with poly(ADP-ribose) polymerase activity. Human tankyrases post-translationally modify multiple proteins involved in processes including maintenance of telomere length, sister telomere association, and trafficking of glut4-containing vesicles. To date, however, little is known about in vivo functions for tankyrases. We recently reported that body size was significantly reduced in mice deficient for tankyrase 2, but that these mice otherwise appeared developmentally normal. In the present study, we report generation of tankyrase 1-deficient and tankyrase 1 and 2 double-deficient mice, and use of these mutant strains to systematically assess candidate functions of tankyrase 1 and tankyrase 2 in vivo. No defects were observed in development, telomere length maintenance, or cell cycle regulation in tankyrase 1 or tankyrase 2 knockout mice. In contrast to viability and normal development of mice singly deficient in either tankyrase, deficiency in both tankyrase 1 and tankyrase 2 results in embryonic lethality by day 10, indicating that there is substantial redundancy between tankyrase 1 and tankyrase 2, but that tankyrase function is essential for embryonic development

    Attitudes towards gender roles and prevalence of intimate partner violence perpetrated against pregnant and postnatal women: Differences between women immigrants from conflict-affected countries and women born in Australia

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    BACKGROUND: The aim was to compare, for the first time in a large systematic study, women born in conflict-affected countries who immigrated to Australia with women born in Australia for attitudes towards gender roles and men\u27s use of IPV and the actual prevalence of IPV. The study also examined if any associations remained across the two timepoints of pregnancy and postpartum. METHODS: Women were interviewed during their first visit to one of three Australian public hospital antenatal clinics and re-interviewed at home six months after giving birth. A total of 1111 women completed both interviews, 583 were born in conflict-affected countries and 528 born in Australia. Associations between attitudes towards gender roles and men\u27s use of IPV, socio-demographic characteristics and reported actual experiences of IPV were examined using bivariate and multiple logistic regression analyses. RESULTS: Attitudes toward inequitable gender roles including those that condone men\u27s use of IPV, and prevalence of IPV, were significantly higher (p \u3c 0.001) among women born in conflict-affected countries compared to Australia-born women. Women born in conflict-affected countries with the strongest held attitudes towards gender roles and men\u27s use of IPV had an adjusted odds ratio (aOR) of 3.18 for IPV at baseline (95% CI 1.85-5.47) and an aOR of 1.83 for IPV at follow-up (95% CI 1.11-3.01). Women born in Australia with the strongest held attitudes towards gender roles and IPV had an aOR of 7.12 for IPV at baseline (95% CI 2.12-23.92) and an aOR of 10.59 for IPV at follow-up (95% CI 2.21-50.75). CONCLUSIONS: Our results underscore the need for IPV prevention strategies sensitively targeted to communities from conflict-affected countries, and for awareness among clinicians of gender role attitudes that may condone men\u27s use of IPV, and the associated risk of IPV. The study supports the need for culturally informed national strategies to promote gender equality and to challenge practices and attitudes that condone men\u27s violence in spousal relationships

    Sister telomeres rendered dysfunctional by persistent cohesion are fused by NHEJ

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    Telomeres protect chromosome ends from being viewed as double-strand breaks and from eliciting a DNA damage response. Deprotection of chromosome ends occurs when telomeres become critically short because of replicative attrition or inhibition of TRF2. In this study, we report a novel form of deprotection that occurs exclusively after DNA replication in S/G2 phase of the cell cycle. In cells deficient in the telomeric poly(adenosine diphosphate ribose) polymerase tankyrase 1, sister telomere resolution is blocked. Unexpectedly, cohered sister telomeres become deprotected and are inappropriately fused. In contrast to telomeres rendered dysfunctional by TRF2, which engage in chromatid fusions predominantly between chromatids from different chromosomes (Bailey, S.M., M.N. Cornforth, A. Kurimasa, D.J. Chen, and E.H. Goodwin. 2001. Science. 293:2462–2465; Smogorzewska, A., J. Karlseder, H. Holtgreve-Grez, A. Jauch, and T. de Lange. 2002. Curr. Biol. 12:1635–1644), telomeres rendered dysfunctional by tankyrase 1 engage in chromatid fusions almost exclusively between sister chromatids. We show that cohered sister telomeres are fused by DNA ligase IV–mediated nonhomologous end joining. These results demonstrate that the timely removal of sister telomere cohesion is essential for the formation of a protective structure at chromosome ends after DNA replication in S/G2 phase of the cell cycle

    Prevention of Hepatic Steatosis and Hepatic Insulin Resistance by Knockdown of cAMP Response Element-Binding Protein

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    SummaryIn patients with poorly controlled type 2 diabetes mellitus (T2DM), hepatic insulin resistance and increased gluconeogenesis contribute to fasting and postprandial hyperglycemia. Since cAMP response element-binding protein (CREB) is a key regulator of gluconeogenic gene expression, we hypothesized that decreasing hepatic CREB expression would reduce fasting hyperglycemia in rodent models of T2DM. In order to test this hypothesis, we used a CREB-specific antisense oligonucleotide (ASO) to knock down CREB expression in liver. CREB ASO treatment dramatically reduced fasting plasma glucose concentrations in ZDF rats, ob/ob mice, and an STZ-treated, high-fat-fed rat model of T2DM. Surprisingly, CREB ASO treatment also decreased plasma cholesterol and triglyceride concentrations, as well as hepatic triglyceride content, due to decreases in hepatic lipogenesis. These results suggest that CREB is an attractive therapeutic target for correcting both hepatic insulin resistance and dyslipidemia associated with nonalcoholic fatty liver disease (NAFLD) and T2DM

    Dark sectors 2016 Workshop: community report

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    This report, based on the Dark Sectors workshop at SLAC in April 2016, summarizes the scientific importance of searches for dark sector dark matter and forces at masses beneath the weak-scale, the status of this broad international field, the important milestones motivating future exploration, and promising experimental opportunities to reach these milestones over the next 5-10 years

    Current understanding of the human microbiome

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    Author Posting. © The Author(s), 2018. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature Medicine 24 (2018): 392–400, doi:10.1038/nm.4517.Our understanding of the link between the human microbiome and disease, including obesity, inflammatory bowel disease, arthritis and autism, is rapidly expanding. Improvements in the throughput and accuracy of DNA sequencing of the genomes of microbial communities associated with human samples, complemented by analysis of transcriptomes, proteomes, metabolomes and immunomes, and mechanistic experiments in model systems, have vastly improved our ability to understand the structure and function of the microbiome in both diseased and healthy states. However, many challenges remain. In this Review, we focus on studies in humans to describe these challenges, and propose strategies that leverage existing knowledge to move rapidly from correlation to causation, and ultimately to translation.Many of the studies described here in our laboratories were supported by the NIH, NSF, DOE, and the Alfred P. Sloan Foundation.2018-10-1

    JWST reveals a possible z11z \sim 11 galaxy merger in triply-lensed MACS0647-JD

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    MACS0647-JD is a triply-lensed z11z\sim11 galaxy originally discovered with the Hubble Space Telescope. Here we report new JWST imaging, which clearly resolves MACS0647-JD as having two components that are either merging galaxies or stellar complexes within a single galaxy. Both are very small, with stellar masses 108M\sim10^8\,M_\odot and radii r<100pcr<100\,\rm pc. The brighter larger component "A" is intrinsically very blue (β2.6\beta\sim-2.6), likely due to very recent star formation and no dust, and is spatially extended with an effective radius 70pc\sim70\,\rm pc. The smaller component "B" appears redder (β2\beta\sim-2), likely because it is older (100200Myr100-200\,\rm Myr) with mild dust extinction (AV0.1magA_V\sim0.1\,\rm mag), and a smaller radius 20pc\sim20\,\rm pc. We identify galaxies with similar colors in a high-redshift simulation, finding their star formation histories to be out of phase. With an estimated stellar mass ratio of roughly 2:1 and physical projected separation 400pc\sim400\,\rm pc, we may be witnessing a galaxy merger 400 million years after the Big Bang. We also identify a candidate companion galaxy C 3kpc\sim3\,{\rm kpc} away, likely destined to merge with galaxies A and B. The combined light from galaxies A+B is magnified by factors of \sim8, 5, and 2 in three lensed images JD1, 2, and 3 with F356W fluxes 322\sim322, 203203, 86nJy86\,\rm nJy (AB mag 25.1, 25.6, 26.6). MACS0647-JD is significantly brighter than other galaxies recently discovered at similar redshifts with JWST. Without magnification, it would have AB mag 27.3 (MUV=20.4M_{UV}=-20.4). With a high confidence level, we obtain a photometric redshift of z=10.6±0.3z=10.6\pm0.3 based on photometry measured in 6 NIRCam filters spanning 15μm1-5\rm\mu m, out to 4300A˚4300\,\r{A} rest-frame. JWST NIRSpec observations planned for January 2023 will deliver a spectroscopic redshift and a more detailed study of the physical properties of MACS0647-JD.Comment: 27 pages, 14 figures, submitted to Natur

    The Atacama Cosmology Telescope: A Measurement of the DR6 CMB Lensing Power Spectrum and its Implications for Structure Growth

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    We present new measurements of cosmic microwave background (CMB) lensing over 94009400 sq. deg. of the sky. These lensing measurements are derived from the Atacama Cosmology Telescope (ACT) Data Release 6 (DR6) CMB dataset, which consists of five seasons of ACT CMB temperature and polarization observations. We determine the amplitude of the CMB lensing power spectrum at 2.3%2.3\% precision (43σ43\sigma significance) using a novel pipeline that minimizes sensitivity to foregrounds and to noise properties. To ensure our results are robust, we analyze an extensive set of null tests, consistency tests, and systematic error estimates and employ a blinded analysis framework. The baseline spectrum is well fit by a lensing amplitude of Alens=1.013±0.023A_{\mathrm{lens}}=1.013\pm0.023 relative to the Planck 2018 CMB power spectra best-fit Λ\LambdaCDM model and Alens=1.005±0.023A_{\mathrm{lens}}=1.005\pm0.023 relative to the ACT DR4+WMAP\text{ACT DR4} + \text{WMAP} best-fit model. From our lensing power spectrum measurement, we derive constraints on the parameter combination S8CMBLσ8(Ωm/0.3)0.25S^{\mathrm{CMBL}}_8 \equiv \sigma_8 \left({\Omega_m}/{0.3}\right)^{0.25} of S8CMBL=0.818±0.022S^{\mathrm{CMBL}}_8= 0.818\pm0.022 from ACT DR6 CMB lensing alone and S8CMBL=0.813±0.018S^{\mathrm{CMBL}}_8= 0.813\pm0.018 when combining ACT DR6 and Planck NPIPE CMB lensing power spectra. These results are in excellent agreement with Λ\LambdaCDM model constraints from Planck or ACT DR4+WMAP\text{ACT DR4} + \text{WMAP} CMB power spectrum measurements. Our lensing measurements from redshifts z0.5z\sim0.5--55 are thus fully consistent with Λ\LambdaCDM structure growth predictions based on CMB anisotropies probing primarily z1100z\sim1100. We find no evidence for a suppression of the amplitude of cosmic structure at low redshiftsComment: 45+21 pages, 50 figures. Prepared for submission to ApJ. Also see companion papers Madhavacheril et al and MacCrann et a
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