The rockefeller university

Understanding the antibody response to HIV-1 in humans that show broad neutralizing serologic activity is a crucial step in trying to reproduce such responses by vaccination. Investigating antibodies with cross clade reactivity is particularly important as these antibodies may target conserved epitopes on the HIV envelope gp160 protein. To this end we have used a clade B YU-2 gp140 trimeric antigen and single-cell antibody cloning methods to obtain 189 new anti-gp140 antibodies representing 51 independent B cell clones from the IgG memory B cells of 3 patients infected with HIV-1 clade A or B viruses and exhibiting broad neutralizing serologic activity. Our results support previous findings showing a diverse antibody response to HIV gp140 envelope protein, characterized by differentially expanded B-cell clones producing highly hypermutated antibodies with heterogenous gp140-specificity and neutralizing activity. In addition to their high-affinity binding to the HIV spike, the vast majority of the new anti-gp140 antibodies are also polyreactive. Although none of the new antibodies are as broad or potent as VRC01 or PG9, two clonally-related antibodies isolated from a clade A HIV-1 infected donor, directed against the gp120 variable loop 3, rank in the top 5% of the neutralizers identified in our large collection of 185 unique gp140-specific antibodies in terms of breadth and potency.

Many changes produced by chronic stress are similar to those seen in cannabinoid CB1 receptor-deficient mice. In the current study, we examined both anxiety-like behavior and dendritic complexity within the prefrontal cortex and basolateral amygdala (BLA) in wild-type and CB1 receptor-deficient mice, under basal conditions and following exposure to 21 days of protracted restraint stress. CB1 receptor-deficient mice exhibited increased indices of anxiety in the elevated plus maze under basal conditions that were similar in magnitude to changes seen in wild-type mice exposed to chronic stress. Chronic stress or deletion of the CB1 receptor also produced a reduction in both apical dendritic length and branch points of neurons within layer II/III of the prelimbic region of the prefrontal cortex. Pyramidal neurons in the (BLA) of CB1 receptor-deficient mice were found to have increased dendritic length compared with wild type. Chronic stress increased dendritic length of these amygdalar neurons in both wild-type and CB1 receptor-deficient mice. Collectively, these data demonstrate that loss of cannabinoid CB1 receptor signaling produces a chronic stress-like phenotype under basal conditions and provide a putative neural substrate that may subserve the changes in emotional behavior seen following disruption of CB1 receptor signaling.

G protein-gated K+ channels (Kir3.1-Kir3.4) control electrical excitability in many different cells. Among their functions relevant to human physiology and disease, they regulate the heart rate and govern a wide range of neuronal activities. Here, we present the first crystal structures of a G protein-gated K+ channel. By comparing the wild-type structure to that of a constitutively active mutant, we identify a global conformational change through which G proteins could open a G loop gate in the cytoplasmic domain. The structures of both channels in the absence and presence of PIP2 suggest that G proteins open only the G loop gate in the absence of PIP2, but in the presence of PIP2 the G loop gate and a second inner helix gate become coupled, so that both gates open. We also identify a strategically located Na+ ion-binding site, which would allow intracellular Na+ to modulate GIRK channel activity. These data provide a structural basis for understanding multiligand regulation of GIRK channel gating.

The cell membranes in the hair bundle of an auditory hair cell confront a difficult task as the bundle oscillates in response to sound: for efficient mechanotransduction, all the component stereocilia of the hair bundle must move essentially in unison, shearing at their tips yet maintaining contact without membrane fusion. One mechanism by which this cohesion might occur is counterion-mediated attachment between glycan components of apposed stereociliary membranes. Using capillary electrophoresis, we showed that the stereociliary glycocalyx acts as a negatively charged polymer brush. We found by force-sensing photomicrometry that the stereocilia formed elastic connections with one another to various degrees depending on the surrounding ionic environment and the presence of N-linked sugars. Mg(2+) was a more potent mediator of attachment than was Ca(2+). The forces between stereocilia produced chaotic stick-slip behavior. These results indicate that counterion-mediated interactions in the glycocalyx contribute to the stereociliary coherence that is essential for hearing.

p11 is an adaptor protein which binds to serotonin 5-HT1B receptors and 5-HT4 receptors and regulates their localization at the cell surface. In the present study, we examined to what extent pll containing neurons co-expressed 5-HT1BR and/or 5-HT4R in cerebral cortex, hippocampus, cerebellum and caudateputamen. A triple-labeling immunohistochemical approach was taken using antibodies to detect native p11 and 5-HT1BR combined with visualization of EGFP driven under the 5-HT4R promoter in BAC-transgenic mice. In the caudate-putamen, the hippocampal pyramidal cell layer of CA1 and the hippocampal granule cell layer of dentate gyrus, most pll containing cells co-expressed both 5-HT1BR and 5-HT4R. In the cingulate cortex, stratum radiatum/oriens of CA1, hilus of the dentate gyrus and cerebellar cortex, many cells co-expressed p11 and 5-HT1BR, but not 5-HT4R. In the studied brain regions, few cells solely expressed p11 without any significant expression of 5-HT1BR or 5-HT4R. It can be concluded that pll is anatomically positioned to modulate serotonin neurotransmission, via 5-HT1BR and 5-HT4R, in brain regions important for emotionality, cognition and locomotion. This article is part of a Special Issue entitled 'Serotonin: The New Wave'. (C) 2011 Elsevier Ltd. All rights reserved.

This article reports a measurement of the production cross section of prompt isolated photon pairs in proton-antiproton collisions at root s = 1.96 TeV using the CDF II detector at the Fermilab Tevatron collider. The data correspond to an integrated luminosity of 5.36 fb(-1). The cross section is presented as a function of kinematic variables sensitive to the reaction mechanisms. The results are compared with three perturbative QCD calculations: (1) a leading-order parton shower Monte Carlo, (2) a fixed next-to-leading-order calculation and (3) a next-to-leading-order/next-to-next-to-leading-log resummed calculation. The comparisons show that, within their known limitations, all calculations predict the main features of the data, but no calculation adequately describes all aspects of the data.

Background-Myocardial infarction leads to cardiac remodeling and development of heart failure. Insufficient myocardial capillary density after myocardial infarction has been identified as a critical event in this process, although the underlying mechanisms of cardiac angiogenesis are mechanistically not well understood. Methods and Results-Here, we show that the small noncoding RNA microRNA-24 (miR-24) is enriched in cardiac endothelial cells and considerably upregulated after cardiac ischemia. MiR-24 induces endothelial cell apoptosis, abolishes endothelial capillary network formation on Matrigel, and inhibits cell sprouting from endothelial spheroids. These effects are mediated through targeting of the endothelium-enriched transcription factor GATA2 and the p21-activated kinase PAK4, which were identified by bioinformatic predictions and validated by luciferase gene reporter assays. Respective downstream signaling cascades involving phosphorylated BAD (Bcl-XL/Bcl-2-associated death promoter) and Sirtuin1 were identified by transcriptome, protein arrays, and chromatin immunoprecipitation analyses. Overexpression of miR-24 or silencing of its targets significantly impaired angiogenesis in zebrafish embryos. Blocking of endothelial miR-24 limited myocardial infarct size of mice via prevention of endothelial apoptosis and enhancement of vascularity, which led to preserved cardiac function and survival. Conclusions-Our findings indicate that miR-24 acts as a critical regulator of endothelial cell apoptosis and angiogenesis and is suitable for therapeutic intervention in the setting of ischemic heart disease. (Circulation. 2011; 124: 720-730.)

A measurement is presented of the charged hadron multiplicity in hadronic PbPb collisions, as a function of pseudorapidity and centrality, at a collision energy of 2.76 TeV per nucleon pair. The data sample is collected using the CMS detector and a minimum-bias trigger, with the CMS solenoid off. The number of charged hadrons is measured both by counting the number of reconstructed particle hits and by forming hit doublets of pairs of layers in the pixel detector. The two methods give consistent results. The charged hadron multiplicity density, dN(ch)/d eta vertical bar(eta=0), for head-on collisions is found to be 1612 +/- 55, where the uncertainty is dominated by systematic effects. Comparisons of these results to previous measurements and to various models are also presented.

Background: Hybridization can have complex effects on evolutionary dynamics in ants because of the combination of haplodiploid sex-determination and eusociality. While hybrid non-reproductive workers have been found in a range of species, examples of gene-flow via hybrid queens and males are rare. We studied hybridization in East African army ants (Dorylus subgenus Anomma) using morphology, mitochondrial DNA sequences, and nuclear microsatellites. Results: While the mitochondrial phylogeny had a strong geographic signal, different species were not recovered as monophyletic. At our main study site at Kakamega Forest, a mitochondrial haplotype was shared between a "Dorylus molestus-like" and a "Dorylus wilverthi-like" form. This pattern is best explained by introgression following hybridization between D. molestus and D. wilverthi. Microsatellite data from workers showed that the two morphological forms correspond to two distinct genetic clusters, with a significant proportion of individuals being classified as hybrids. Conclusions: We conclude that hybridization and gene-flow between the two army ant species D. molestus and D. wilverthi has occurred, and that mating between the two forms continues to regularly produce hybrid workers. Hybridization is particularly surprising in army ants because workers have control over which males are allowed to mate with a young virgin queen inside the colony.