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Found 37443 matches. Displaying 4181-4190
Chakraborty M, Chen LF, Fridel EE, Klein ME, Senft RA, Sarkar A, Jarvis ED
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Overexpression of human NR2B receptor subunit in LMAN causes stuttering and song sequence changes in adult zebra finches (opens in new window)

SCIENTIFIC REPORTS 2017 APR 21; 7(?):? Article 942
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Zebra finches (Taeniopygia guttata) learn to produce songs in a manner reminiscent of spoken language development in humans. One candidate gene implicated in influencing learning is the N-methyl-D-aspartate (NMDA) subtype 2B glutamate receptor (NR2B). Consistent with this idea, NR2B levels are high in the song learning nucleus LMAN (lateral magnocellular nucleus of the anterior nidopallium) during juvenile vocal learning, and decreases to low levels in adults after learning is complete and the song becomes more stereotyped. To test for the role of NR2B in generating song plasticity, we manipulated NR2B expression in LMAN of adult male zebra finches by increasing its protein levels to those found in juvenile birds, using a lentivirus containing the full-length coding sequence of the human NR2B subunit. We found that increased NR2B expression in adult LMAN induced increases in song sequence diversity and slower song tempo more similar to juvenile songs, but also increased syllable repetitions similar to stuttering. We did not observe these effects in control birds with overexpression of NR2B outside of LMAN or with the green fluorescent protein (GFP) in LMAN. Our results suggest that low NR2B subunit expression in adult LMAN is important in conserving features of stereotyped adult courtship song.
Cohn LB, Nussenzweig MC
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HIV: Persistence through division (opens in new window)

JOURNAL OF EXPERIMENTAL MEDICINE 2017 APR; 214(4):875-876
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Gonzales J, Bhupathiraju NVSDK, Perea W, Chu H, Berisha N, Bueno V, Dodic N, Rozenberg J, Greenbaum NL, Drain CM
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Facile synthesis of chlorin bioconjugates by a series of click reactions (opens in new window)

CHEMICAL COMMUNICATIONS 2017 APR 4; 53(26):3773-3776
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A multifunctional chlorin platform appended with four short polyethylene glycols and a carboxylate-linker allows rapid conjugation to biotargeting motifs such as proteins and oligonucleotides. The stability and photophysical properties of the chlorin enable development of diagnostics, imaging, molecular tracking, and theranostics.
Mohammed AM, Sulc P, Zenk J, Schulman R
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Self-assembling DNA nanotubes to connect molecular landmarks (opens in new window)

NATURE NANOTECHNOLOGY 2017 APR; 12(4):312-316
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Within cells, nanostructures are often organized using local assembly rules that produce long-range order(1,2). Because these rules can take into account the cell's current structure and state, they can enable complexes, organelles or cytoskeletal structures to assemble around existing cellular components to form architectures(3-6). Although many methods for self-assembling biomolecular nanostructures have been developed(7-11), few can be programmed to assemble structures whose form depends on the identity and organization of structures already present in the environment. Here, we demonstrate that DNA nanotubes can grow to connect pairs of molecular landmarks with different separation distances and relative orientations. DNA tile nanotubes nucleate at these landmarks and grow while their free ends diffuse. The nanotubes can then join end to end to form stable connections, with unconnected nanotubes selectively melted away. Connections form between landmark pairs separated by 1-10 mu m in more than 75% of cases and can span a surface or three dimensions. This point-to-point assembly process illustrates how self-assembly kinetics can be designed to produce structures with a desired physical property rather than a specific shape.
Nectow AR, Moya MV, Ekstrand MI, Mousa A, McGuire KL, Sferrazza CE, Field BC, Rabinowitz GS, Sawicka K, Liang YP, Friedman JM, Heintz N, Schmidt EF
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Rapid Molecular Profiling of Defined Cell Types Using Viral TRAP (opens in new window)

CELL REPORTS 2017 APR 18; 19(3):655-667
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Translational profiling methodologies enable the systematic characterization of cell types in complex tissues, such as the mammalian brain, where neuronal isolation is exceptionally difficult. Here, we report a versatile strategy for profiling CNS cell types in a spatiotemporally restricted fashion by engineering a Cre-dependent adeno-associated virus expressing an EGFP-tagged ribosomal protein (AAV-FLEXEGFPL10a) to access translating mRNAs by translating ribosome affinity purification (TRAP). We demonstrate the utility of this AAV to target a variety of genetically and anatomically defined neural populations expressing Cre recombinase and illustrate the ability of this viralTRAP(vTRAP) approach to recapitulate the molecular profiles obtained by bacTRAP in corticothalamic neurons across multiple serotypes. Furthermore, spatially restricting adeno-associated virus (AAV) injections enabled the elucidation of regional differences in gene expression within this cell type. Altogether, these results establish the broad applicability of the vTRAP strategy for the molecular dissection of any CNS or peripheral cell type that can be engineered to express Cre.
Yin L, Ren HC, Lee TK, Hou DF
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Momentum analyticity of the holographic electric polarizability in 2+1 dimensions (opens in new window)

JOURNAL OF HIGH ENERGY PHYSICS 2017 APR 21; ?(4):? Article 126
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The static electric polarization of a holographic field theory dual to the Einstein-Maxwell theory in the background of AdS(4) with a Reissner-Nordstrom (AdS-RN) black hole is investigated. We prove that the holographic polarization is a meromorphic functions in complex momentum plane and locate analytically the asymptotic distribution of the poles along two straight lines parallel to the imaginary axis for a large momentum magnitude. The results are compared with the numerical result on Friedel-like poles of the same holographic model reported in the literature and with the momentum singularities of the one-loop polarization in weak-coupling spinor QED(3) and scalar QED(3) with the similarities and differences discussed.
Klinglmayr J, Bettstetter C, Timme M, Kirst C
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Convergence of Self-Organizing Pulse-Coupled Oscillator Synchronization in Dynamic Networks (opens in new window)

IEEE TRANSACTIONS ON AUTOMATIC CONTROL 2017 APR; 62(4):1606-1619
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The theory of pulse-coupled oscillators provides a framework to formulate and develop self-organizing synchronization strategies for wireless communications and mobile computing. These strategies show low complexity and are adaptive to changes in the network. Even though several protocols have been proposed and theoretical insight was gained there is no proof that guarantees synchronization of the oscillator phases in general dynamic coupling topologies under technological constraints. Here, we introduce a family of coupling strategies for pulse-coupled oscillators and prove that synchronizationemerges for systems with arbitrary connected and dynamic topologies, individually changing signal propagation and processing delays, and stochastic pulse emission. It is shown by simulations how unreliable links or intentionally incomplete communication between oscillators can improve synchronization performance.
Garzia A, Meyer C, Morozov P, Sajek M, Tuschl T
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Optimization of PAR-CLIP for transcriptome-wide identification of binding sites of RNA-binding proteins (opens in new window)

METHODS 2017 APR 15; 118(?):24-40
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Photoactivatable-Ribonucleoside-Enhanced Crosslinking and Immunoprecipitation (PAR-CLIP) in combination with next-generation sequencing is a powerful method for identifying endogenous targets of RNA binding proteins (RBPs). Depending on the characteristics of each RBP, key steps in the PAR-CLIP procedure must be optimized. Here we present a comprehensive step-by-step PAR-CLIP protocol with detailed explanations of the critical steps. Furthermore, we report the application of a new PAR-CLIP data analysis pipeline to three distinct RBPs targeting different annotation categories of cellular RNAs. (C) 2016 Elsevier Inc. All rights reserved.
Blanco-Melo D, Gifford RJ, Bieniasz PD
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Co-option of an endogenous retrovirus envelope for host defense in hominid ancestors (opens in new window)

ELIFE 2017 APR 11; 6(?):? Article e22519
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Endogenous retroviral sequences provide a molecular fossil record of ancient infections whose analysis might illuminate mechanisms of viral extinction. A close relative of gammaretroviruses, HERV-T, circulated in primates for similar to 25 million years (MY) before apparent extinction within the past similar to 8 MY. Construction of a near-complete catalog of HERV-T fossils in primate genomes allowed us to estimate a similar to 32 MY old ancestral sequence and reconstruct a functional envelope protein (ancHTenv) that could support infection of a pseudotyped modern gammaretrovirus. Using ancHTenv, we identify monocarboxylate transporter-1 (MCT-1) as a receptor used by HERV-T for attachment and infection. A single HERV-T provirus in hominid genomes includes an env gene (hsaHTenv) that has been uniquely preserved. This apparently exapted HERV-T env could not support virion infection but could block ancHTenv mediated infection, by causing MCT-1 depletion from cell surfaces. Thus, hsaHTenv may have contributed to HERV-T extinction, and could also potentially regulate cellular metabolism.
Larhammar M, Huntwork-Rodriguez S, Jiang ZY, Solanoy H, Ghosh AS, Wang B, Kaminker JS, Huang K, Eastham-Anderson J, Siu M, Modrusan Z, Farley MM, Tessier-Lavigne M, Lewcock JW, Watkins TA
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Dual leucine zipper kinase-dependent PERK activation contributes to neuronal degeneration following insult (opens in new window)

ELIFE 2017 APR 25; 6(?):? Article e20725
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The PKR-like endoplasmic reticulum kinase (PERK) arm of the Integrated Stress Response (ISR) is implicated in neurodegenerative disease, although the regulators and consequences of PERK activation following neuronal injury are poorly understood. Here we show that PERK signaling is a component of the mouse MAP kinase neuronal stress response controlled by the Dual Leucine Zipper Kinase (DLK) and contributes to DLK-mediated neurodegeneration. We find that DLK-activating insults ranging from nerve injury to neurotrophin deprivation result in both c-Jun N-terminal Kinase (JNK) signaling and the PERK- and ISR-dependent upregulation of the Activating Transcription Factor 4 (ATF4). Disruption of PERK signaling delays neurodegeneration without reducing JNK signaling. Furthermore, DLK is both sufficient for PERK activation and necessary for engaging the ISR subsequent to JNK-mediated retrograde injury signaling. These findings identify DLK as a central regulator of not only JNK but also PERK stress signaling in neurons, with both pathways contributing to neurodegeneration.