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Found 37684 matches. Displaying 4441-4450
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

METHODS 2017 APR 15; 118(?):24-40
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

ELIFE 2017 APR 11; 6(?):? Article e22519
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

ELIFE 2017 APR 25; 6(?):? Article e20725
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.
Papp KA, Blauvelt A, Bukhalo M, Gooderham M, Krueger J, Lacour JP, Menter A, Philipp S, Sofen H, Tyring S, Berner BR, Visvanathan S, Pamulapati C, Bennett N, Flack M, Scholl P, Padula SJ
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Risankizumab versus Ustekinumab for Moderate-to-Severe Plaque Psoriasis

NEW ENGLAND JOURNAL OF MEDICINE 2017 APR 20; 376(16):1551-1560
BACKGROUND Interleukin-23 is thought to be critical to the pathogenesis of psoriasis. We compared risankizumab (BI 655066), a humanized IgG1 monoclonal antibody that inhibits interleukin-23 by specifically targeting the p19 subunit and thus prevents interleukin-23 signaling, and ustekinumab, an interleukin-12 and interleukin-23 inhibitor, in patients with moderate-to-severe plaque psoriasis. METHODS We randomly assigned a total of 166 patients to receive subcutaneous injections of risankizumab (a single 18-mg dose at week 0 or 90-mg or 180-mg doses at weeks 0, 4, and 16) or ustekinumab (45 or 90 mg, according to body weight, at weeks 0, 4, and 16). The primary end point was a 90% or greater reduction from baseline in the Psoriasis Area and Severity Index (PASI) score at week 12. RESULTS At week 12, the percentage of patients with a 90% or greater reduction in the PASI score was 77% (64 of 83 patients) for risankizumab (90-mg and 180-mg groups, pooled), as compared with 40% (16 of 40 patients) for ustekinumab (P<0.001); the percentage of patients with a 100% reduction in the PASI score was 45% in the pooled 90-mg and 180-mg risankizumab groups, as compared with 18% in the ustekinumab group. Efficacy was generally maintained up to 20 weeks after the final dose of 90 or 180 mg of risankizumab. In the 18-mg and 90-mg risankizumab groups and the ustekinumab group, 5 patients (12%), 6 patients (15%), and 3 patients (8%), respectively, had serious adverse events, including two basal-cell carcinomas and one major cardiovascular adverse event; there were no serious adverse events in the 180-mg risankizumab group. CONCLUSIONS In this phase 2 trial, selective blockade of interleukin-23 with risankizumab was associated with clinical responses superior to those associated with ustekinumab. This trial was not large enough or of long enough duration to draw conclusions about safety.
Rolo J, Worning P, Nielsen JB, Sobral R, Bowden R, Bouchami O, Damborg P, Guardabassi L, Perreten V, Westh H, Tomasz A, de Lencastre H, Miragaia M
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Evidence for the evolutionary steps leading to mecA-mediated beta-lactam resistance in staphylococci

PLOS GENETICS 2017 APR; 13(4):? Article e1006674
The epidemiologically most important mechanism of antibiotic resistance in Staphylococcus aureus is associated with mecA-an acquired gene encoding an extra penicillin-binding protein (PBP2a) with low affinity to virtually all beta-lactams. The introduction of mecA into the S. aureus chromosome has led to the emergence of methicillin-resistant S. aureus (MRSA) pandemics, responsible for high rates of mortality worldwide. Nonetheless, little is known regarding the origin and evolution of mecA. Different mecA homologues have been identified in species belonging to the Staphylococcus sciuri group representing the most primitive staphylococci. In this study we aimed to identify evolutionary steps linking these mecA precursors to the beta-lactam resistance gene mecA and the resistance phenotype. We sequenced genomes of 106 S. sciuri, S. vitulinus and S. fleurettii strains and determined their oxacillin susceptibility profiles. Single-nucleotide polymorphism (SNP) analysis of the core genome was performed to assess the genetic relatedness of the isolates. Phylogenetic analysis of the mecA gene homologues and promoters was achieved through nucleotide/amino acid sequence alignments and mutation rates were estimated using a Bayesian analysis. Furthermore, the predicted structure of mecA homologue-encoded PBPs of oxacillin-susceptible and -resistant strains were compared. We showed for the first time that oxacillin resistance in the S. sciuri group has emerged multiple times and by a variety of different mechanisms. Development of resistance occurred through several steps including structural diversification of the non-binding domain of native PBPs; changes in the promoters of mecA homologues; acquisition of SCCmec and adaptation of the bacterial genetic background. Moreover, our results suggest that it was exposure to beta-lactams in human-created environments that has driven evolution of native PBPs towards a resistance determinant. The evolution of beta-lactam resistance in staphylococci highlights the numerous resources available to bacteria to adapt to the selective pressure of antibiotics.
Tarlinton D, Victora G
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Editorial overview: Germinal centers and memory B-cells: from here to eternity

CURRENT OPINION IN IMMUNOLOGY 2017 APR; 45(?):V-VIII
Fluorescence in situ hybridization (FISH) and immunofluorescence (IF) are sensitive techniques used for detecting nucleic acids and proteins in cultured cells. However, these techniques are rarely applied together, and standard protocols are not readily compatible for sequential application on the same specimen. Here, we provide a user-friendly step-by-step protocol to perform multicolor RNA-FISH in combination with IF to simultaneously detect the subcellular localization of distinct RNAs and proteins in cultured cells. We demonstrate the use of our protocol by analyzing changes in the subcellular distribution of RNAs and proteins in cells exposed to a variety of stress conditions. (C) 2016 Elsevier Inc. All rights reserved.
Gleicher N, Vidali A, Braverman J, Kushnir VA, Barad DH, Hudson C, Wu YG, Wang Q, Zhang L
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Response to comment on: Gleicher N et al., 2016. Reprod biol endocrinol Sep 5; 14(1): 54

REPRODUCTIVE BIOLOGY AND ENDOCRINOLOGY 2017 APR 5; 15(?):1-2
We appreciate the interest of Tiegs et al. in our manuscript [1] but find the criticism surprising. When we wrote our paper, their abstract had been published in 2015 in Fertility& Sterility [2]. It, therefore, was appropriately referenced, while their full length manuscript, in contrast, had not yet been published and, therefore, was at the time unknown to us. The manuscript appeared only at the end of July [3]. Had we known of the manuscript we, of course, would have quoted the full length manuscript, rather than the abstract, though both in the end offered the same data set, out of a total of 525 embryo transfers, reporting on only 5 alleged clinical misdiagnoses that were reanalyzed.
Zeravcic Z, Brenner MP
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Spontaneous emergence of catalytic cycles with colloidal spheres

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2017 APR 25; 114(17):4342-4347
Colloidal particles endowed with specific time-dependent interactions are a promising route for realizing artificial materials that have the properties of living ones. Previous work has demonstrated how this system can give rise to self-replication. Here, we introduce the process of colloidal catalysis, in which clusters of particles catalyze the creation of other clusters through templating reactions. Surprisingly, we find that simple templating rules generically lead to the production of huge numbers of clusters. The templating reactions among this sea of clusters give rise to an exponentially growing catalytic cycle, a specific realization of Dyson's notion of an exponentially growing metabolism. We demonstrate this behavior with a fixed set of interactions between particles chosen to allow a catalysis of a specific six-particle cluster from a specific seven-particle cluster, yet giving rise to the catalytic production of a sea of clusters of sizes between 2 and 11 particles. The fact that an exponentially growing cycle emerges naturally from such a simple scheme demonstrates that the emergence of exponentially growing metabolisms could be simpler than previously imagined.
Roy S, Axup JY, Forsyth JS, Goswami RK, Hutchins BM, Bajuri KM, Kazane SA, Smider VV, Felding BH, Sinha SC
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SMI-Ribosome inactivating protein conjugates selectively inhibit tumor cell growth

CHEMICAL COMMUNICATIONS 2017 APR 18; 53(30):4234-4237
Cell-targeting conjugates of Saporin 6, a ribosome inactivating protein (RIP), were prepared using the Saporin Ala 157 Cys mutant, a small molecule inhibitor (SMI) of integrins alpha(v)beta(3)/alpha(v)beta(5), and a potent cytotoxin, auristatin F (AF). The conjugates selectively and potently inhibited proliferation of tumor cells expressing the target integrins. We anticipate that the small molecule-RIP bioconjugate approach can be broadly applied using other small molecule drugs.