53 research outputs found

    Dynamic Acetylation of All Lysine 4–Methylated Histone H3 in the Mouse Nucleus: Analysis at c-fos and c-jun

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    A major focus of current research into gene induction relates to chromatin and nucleosomal regulation, especially the significance of multiple histone modifications such as phosphorylation, acetylation, and methylation during this process. We have discovered a novel physiological characteristic of all lysine 4 (K4)–methylated histone H3 in the mouse nucleus, distinguishing it from lysine 9–methylated H3. K4-methylated histone H3 is subject to continuous dynamic turnover of acetylation, whereas lysine 9–methylated H3 is not. We have previously reported dynamic histone H3 phosphorylation and acetylation as a key characteristic of the inducible proto-oncogenes c-fos and c-jun. We show here that dynamically acetylated histone H3 at these genes is also K4-methylated. Although all three modifications are proven to co-exist on the same nucleosome at these genes, phosphorylation and acetylation appear transiently during gene induction, whereas K4 methylation remains detectable throughout this process. Finally, we address the functional significance of the turnover of histone acetylation on the process of gene induction. We find that inhibition of turnover, despite causing enhanced histone acetylation at these genes, produces immediate inhibition of gene induction. These data show that all K4-methylated histone H3 is subject to the continuous action of HATs and HDACs, and indicates that at c-fos and c-jun, contrary to the predominant model, turnover and not stably enhanced acetylation is relevant for efficient gene induction

    Electromigration of Single-Layer Clusters

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    Single-layer atom or vacancy clusters in the presence of electromigration are studied theoretically assuming an isotropic medium. A variety of distinctive behaviors distinguish the response in the three standard limiting cases of periphery diffusion (PD), terrace diffusion (TD), and evaporation-condensation (EC). A general model provides power laws describing the size dependence of the drift velocity in these limits, consistent with established results in the case of PD. The validity of the widely used quasistatic limit is calculated. Atom and vacancy clusters drift in opposite directions in the PD limit but in the same direction otherwise. In absence of PD, linear stability analysis reveals a new type of morphological instability, not leading to island break-down. For strong electromigration, Monte Carlo simulations show that clusters then destabilize into slits, in contrast to splitting in the PD limit. Electromigration affects the diffusion coefficient of the cluster and morphological fluctuations, the latter diverging at the instability threshold. An instrinsic attachment-detachment bias displays the same scaling signature as PD in the drift velocity.Comment: 11 pages, 4 figure

    Advancing human health in the decade ahead: pregnancy as a key window for discovery: A Burroughs Wellcome Fund Pregnancy Think Tank.

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    Recent revolutionary advances at the intersection of medicine, omics, data sciences, computing, epidemiology, and related technologies inspire us to ponder their impact on health. Their potential impact is particularly germane to the biology of pregnancy and perinatal medicine, where limited improvement in health outcomes for women and children has remained a global challenge. We assembled a group of experts to establish a Pregnancy Think Tank to discuss a broad spectrum of major gestational disorders and adverse pregnancy outcomes that affect maternal-infant lifelong health and should serve as targets for leveraging the many recent advances. This report reflects avenues for future effects that hold great potential in 3 major areas: developmental genomics, including the application of methodologies designed to bridge genotypes, physiology, and diseases, addressing vexing questions in early human development; gestational physiology, from immune tolerance to growth and the timing of parturition; and personalized and population medicine, focusing on amalgamating health record data and deep phenotypes to create broad knowledge that can be integrated into healthcare systems and drive discovery to address pregnancy-related disease and promote general health. We propose a series of questions reflecting development, systems biology, diseases, clinical approaches and tools, and population health, and a call for scientific action. Clearly, transdisciplinary science must advance and accelerate to address adverse pregnancy outcomes. Disciplines not traditionally involved in the reproductive sciences, such as computer science, engineering, mathematics, and pharmacology, should be engaged at the study design phase to optimize the information gathered and to identify and further evaluate potentially actionable therapeutic targets. Information sources should include noninvasive personalized sensors and monitors, alongside instructive "liquid biopsies" for noninvasive pregnancy assessment. Future research should also address the diversity of human cohorts in terms of geography, racial and ethnic distributions, and social and health disparities. Modern technologies, for both data-gathering and data-analyzing, make this possible at a scale that was previously unachievable. Finally, the psychosocial and economic environment in which pregnancy takes place must be considered to promote the health and wellness of communities worldwide

    The LatMix summer campaign : submesoscale stirring in the upper ocean

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    Author Posting. © American Meteorological Society, 2015. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Bulletin of the American Meteorological Society 96 (2015): 1257–1279, doi:10.1175/BAMS-D-14-00015.1.Lateral stirring is a basic oceanographic phenomenon affecting the distribution of physical, chemical, and biological fields. Eddy stirring at scales on the order of 100 km (the mesoscale) is fairly well understood and explicitly represented in modern eddy-resolving numerical models of global ocean circulation. The same cannot be said for smaller-scale stirring processes. Here, the authors describe a major oceanographic field experiment aimed at observing and understanding the processes responsible for stirring at scales of 0.1–10 km. Stirring processes of varying intensity were studied in the Sargasso Sea eddy field approximately 250 km southeast of Cape Hatteras. Lateral variability of water-mass properties, the distribution of microscale turbulence, and the evolution of several patches of inert dye were studied with an array of shipboard, autonomous, and airborne instruments. Observations were made at two sites, characterized by weak and moderate background mesoscale straining, to contrast different regimes of lateral stirring. Analyses to date suggest that, in both cases, the lateral dispersion of natural and deliberately released tracers was O(1) m2 s–1 as found elsewhere, which is faster than might be expected from traditional shear dispersion by persistent mesoscale flow and linear internal waves. These findings point to the possible importance of kilometer-scale stirring by submesoscale eddies and nonlinear internal-wave processes or the need to modify the traditional shear-dispersion paradigm to include higher-order effects. A unique aspect of the Scalable Lateral Mixing and Coherent Turbulence (LatMix) field experiment is the combination of direct measurements of dye dispersion with the concurrent multiscale hydrographic and turbulence observations, enabling evaluation of the underlying mechanisms responsible for the observed dispersion at a new level.The bulk of this work was funded under the Scalable Lateral Mixing and Coherent Turbulence Departmental Research Initiative and the Physical Oceanography Program. The dye experiments were supported jointly by the Office of Naval Research and the National Science Foundation Physical Oceanography Program (Grants OCE-0751653 and OCE-0751734).2016-02-0

    ASIRI : an ocean–atmosphere initiative for Bay of Bengal

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    Author Posting. © American Meteorological Society, 2016. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Bulletin of the American Meteorological Society 97 (2016): 1859–1884, doi:10.1175/BAMS-D-14-00197.1.Air–Sea Interactions in the Northern Indian Ocean (ASIRI) is an international research effort (2013–17) aimed at understanding and quantifying coupled atmosphere–ocean dynamics of the Bay of Bengal (BoB) with relevance to Indian Ocean monsoons. Working collaboratively, more than 20 research institutions are acquiring field observations coupled with operational and high-resolution models to address scientific issues that have stymied the monsoon predictability. ASIRI combines new and mature observational technologies to resolve submesoscale to regional-scale currents and hydrophysical fields. These data reveal BoB’s sharp frontal features, submesoscale variability, low-salinity lenses and filaments, and shallow mixed layers, with relatively weak turbulent mixing. Observed physical features include energetic high-frequency internal waves in the southern BoB, energetic mesoscale and submesoscale features including an intrathermocline eddy in the central BoB, and a high-resolution view of the exchange along the periphery of Sri Lanka, which includes the 100-km-wide East India Coastal Current (EICC) carrying low-salinity water out of the BoB and an adjacent, broad northward flow (∼300 km wide) that carries high-salinity water into BoB during the northeast monsoon. Atmospheric boundary layer (ABL) observations during the decaying phase of the Madden–Julian oscillation (MJO) permit the study of multiscale atmospheric processes associated with non-MJO phenomena and their impacts on the marine boundary layer. Underway analyses that integrate observations and numerical simulations shed light on how air–sea interactions control the ABL and upper-ocean processes.This work was sponsored by the U.S. Office of Naval Research (ONR) in an ONR Departmental Research Initiative (DRI), Air–Sea Interactions in Northern Indian Ocean (ASIRI), and in a Naval Research Laboratory project, Effects of Bay of Bengal Freshwater Flux on Indian Ocean Monsoon (EBOB). ASIRI–RAWI was funded under the NASCar DRI of the ONR. The Indian component of the program, Ocean Mixing and Monsoons (OMM), was supported by the Ministry of Earth Sciences of India.2017-04-2

    Dynamic histone H3 methylation during gene induction: HYPB/Setd2 mediates all H3K36 trimethylation

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    Understanding the function of histone modifications across inducible genes in mammalian cells requires quantitative, comparative analysis of their fate during gene activation and identification of enzymes responsible. We produced high-resolution comparative maps of the distribution and dynamics of H3K4me3, H3K36me3, H3K79me2 and H3K9ac across c-fos and c-jun upon gene induction in murine fibroblasts. In unstimulated cells, continuous turnover of H3K9 acetylation occurs on all K4-trimethylated histone H3 tails; distribution of both modifications coincides across promoter and 5′ part of the coding region. In contrast, K36- and K79-methylated H3 tails, which are not dynamically acetylated, are restricted to the coding regions of these genes. Upon stimulation, transcription-dependent increases in H3K4 and H3K36 trimethylation are seen across coding regions, peaking at 5′ and 3′ ends, respectively. Addressing molecular mechanisms involved, we find that Huntingtin-interacting protein HYPB/Setd2 is responsible for virtually all global and transcription-dependent H3K36 trimethylation, but not H3K36-mono- or dimethylation, in these cells. These studies reveal four distinct layers of histone modification across inducible mammalian genes and show that HYPB/Setd2 is responsible for H3K36 trimethylation throughout the mouse nucleus

    Management of Patients With Crohn's Disease and Ulcerative Colitis During the Coronavirus Disease-2019 Pandemic: Results of an International Meeting

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    The International Organization for the Study of Inflammatory Bowel Diseases (IOIBD) is the only global organization devoted to the study of and management of the inflammatory bowel diseases (IBDs), namely, Crohn?s disease and ulcerative colitis. Membership is composed of physician-scientists who have established expertise in these diseases. The organization hosts an annual meeting and a number of working groups addressing issues of the epidemiology of IBD, diet and nutrition, and the development and use of treatments for IBD. There are currently 89 members of IOIBD representing 26 different countries. The organization has taken particular interest in the coronavirus disease-2019 (COVID-19) pandemic and how it may affect the IBD patient population. This document summarizes the results of 2 recent virtual meetings of the group and subsequent expert guidance for patients and providers

    Identification and characterisation of alternative forms of SETD2/HYPB (SET domain-containing protein 2 / Huntingtin yeast partner B)

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    SETD2/HYPB (SET domain−containing protein 2 / Huntingtin yeast partner B) is the predominant lysine methyltransferase in mammals that mediates histone H3 lysine-36 (H3K36) trimethylation, which is associated with transcription elongation and RNA splicing. SETD2 is further implicated in p53 function, vascular development, cancer progression and, through Huntingtin-interaction, Huntington's disease. Although different transcripts and putative protein isoforms have been detected previously, their identity, function and significance have not been rigorously investigated. This thesis aims to identify and characterise endogenous transcripts and protein isoforms of SETD2 in mouse fibroblasts. Affnity-purified N- and C-terminal antibodies specifically detected the ≈ 290 kDa methyltransferase (p290SETD2), verified by RNAi, in addition to N terminal-specific ≈ 120 kDa protein, and C terminal-specific forms at ≈ 140 and ≈ 66 kDa (p66), which all appeared too stable to deplete by transient siRNA transfection. Conserved in human and mouse cells, immunodetection of p66 exhibited unusual requirement for denaturation with urea at 95°C. Subcellular fractionation revealed distinct extraction properties of putative isoforms and facilitated partial purification of p66 for proteomic analysis. Co-fractionation and co migration by two-dimensional gel electrophoresis of p66 detected by two independent C terminal antibodies suggested it represents a novel C terminal-specific isoform. Reverse transcription−PCR and DNA-sequencing demonstrated the existence of multiple, alternatively-spliced Setd2 transcripts that plausibly generate truncated proteins. A transcript variant containing a novel complete open-reading-frame, consistent for p66 generation, was identified. Its ectopic expression in mouse fibroblasts produced a distinct SETD2 isoform, whose physical and extraction characteristics were studied in comparison with endogenous immunoforms. In summary, this thesis demonstrates that multiple alternatively-spliced transcripts arise from the Setd2 gene, consistent with immunodetection of several C- and N-terminal-specific putative SETD2 isoforms, additional to the H3K36 methyltransferase. Verification of these isoforms by independent methods would have implications for proposed interactions and function of SETD2 in transcription, epigenetics, cancer development and Huntington’s disease.This thesis is not currently available via ORA

    Effect of TSA Pre-Treatment on TPA-Stimulated MAP Kinase Activation and Transcription Factor Phosphorylation

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    <div><p>(A) Quiescent C3H 10T½ cells were treated with TSA (10 or 500 ng/ml; 5 min to 4 h). Positive controls for MAP kinase activation included ERK1/2 (TPA [T]; 10 min), JNK/SAPKs, and p38 (sAn; 30 to 60 min). “C” indicates control (unstimulated). Cell extracts were analysed by Western blotting with anti-ERK1/2, anti-phospho-p38, and anti–ACTIVE JNK antibodies. The mobility of ERKs is retarded on activation. Activation of p38 and JNK/SAPK results in phosphorylation. Note that anti–ACTIVE JNK also recognises activated ERK1/2 (lane 14).</p> <p>(B) Quiescent C3H 10T½ cells were untreated (−) or pre-treated with TSA (10 or 500 ng/ml; 15 min). Cells were then left unstimulated (C) or stimulated with TPA for 5 to 30 min. Cell extracts were analysed by Western blotting with anti-ERK1/2 antibody.</p> <p>(C) Quiescent C3H 10T½ cells were untreated (−) or pre-treated with TSA (500 ng/ml; 15 min). Cells were stimulated with TPA for 15 to 30 min. Cell extracts were analysed by Western blotting with anti-ATF-2 and anti-phospho-CREB antibodies. Phosphorylation of ATF-2 results in retarded mobility.</p></div
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