The rockefeller university

The semiconservative replication of telomeres is facilitated by the shelterin component TRF1. Without TRF1, replication forks stall in the telomeric repeats, leading to ATR kinase signaling upon S-phase progression, fragile metaphase telomeres that resemble the common fragile sites (CFSs), and the association of sister telomeres. In contrast, TRF1 does not contribute significantly to the end protection functions of shelterin. We addressed the mechanism of TRF1 action using mouse conditional knockouts of BLM, TRF1, TPP1, and Rap1 in combination with expression of TRF1 and TIN2 mutants. The data establish that TRF1 binds BLM to facilitate lagging but not leading strand telomeric DNA synthesis. As the template for lagging strand telomeric DNA synthesis is the TTAGGG repeat strand, TRF1-bound BLM is likely required to remove secondary structures formed by these sequences. In addition, the data establish that TRF1 deploys TIN2 and the TPP1/POT1 heterodimers in shelterin to prevent ATR during telomere replication and repress the accompanying sister telomere associations. Thus, TRF1 uses two distinct mechanisms to promote replication of telomeric DNA and circumvent the consequences of replication stress. These data are relevant to the expression of CFSs and provide insights into TIN2, which is compromised in dyskeratosis congenita (DC) and related disorders.

Neuroinflammation is a feedback mechanism against infection, with recent studies suggesting a neuromodulatory role. The chemokine, (C-C motif) ligand 2 (CCL2), and its receptor, (C-C motif) receptor type 2 (CCR2), affect neuromodulation and migration in response to damage. Although CCL2 co-localizes with neuropeptides in the hypothalamus that control voluntary behavior, the function of CCL2/CCR2 is unknown. This led us to consider the possibility that CCL2 acting through CCR2, under natural conditions, may affect the migration and peptide levels of hypothalamic neurons that control voluntary behavior. This study used primary embryonic hypothalamic neurons to examine the effect of CCL2 on migratory behavior and on levels of the peptides, enkephalin (ENK) and galanin. Treatment with CCL2 led to a significant, dose-dependent increase in the number of migrated neurons and an increase in the velocity and distance traveled. CCL2 also significantly increased the number of ENK-expressing and CCR2/ENK co-expressing neurons and the percentage of neurons that contain higher levels of ENK. Lastly, CCL2 produced a dose-dependent increase in expression of ENK and galanin. These results provide evidence for a stimulatory effect of CCL2 on embryonic hypothalamic neurons involving changes in migratory behavior, expression, and synthesis of neuropeptides that function in controlling behavior.

Brown adipose tissue is the primary site for thermogenesis and can consume, in addition to free fatty acids, a very high amount of glucose from the blood, which can both acutely and chronically affect glucose homeostasis. Here, we show that mechanistic target of rapamycin (mTOR) complex 2 has a novel role in beta(3)-adrenoceptor-stimulated glucose uptake in brown adipose tissue. We show that beta(3)-adrenoceptors stimulate glucose uptake in brown adipose tissue via a signaling pathway that is comprised of two different parts: one part dependent on cAMP-mediated increases in GLUT1 transcription and de novo synthesis of GLUT1 and another part dependent on mTOR complex 2-stimulated translocation of newly synthesized GLUT1 to the plasma membrane, leading to increased glucose uptake. Both parts are essential for beta(3)-adrenoceptor-stimulated glucose uptake. Importantly, the effect of beta(3)-adrenoceptor on mTOR complex 2 is independent of the classical insulin-phosphoinositide 3-kinase-Akt pathway, highlighting a novel mechanism of mTOR complex 2 activation.

During gestation, development proceeds at a pace that is unmatched by any other stage of the life cycle. For these reasons the human fetus is particularly susceptible not only to organizing influences, but also to pathogenic disorganizing influences. Growing evidence suggests that exposure to prenatal adversity leads to neurological changes that underlie lifetime risks for mental illness. Beginning early in gestation, males and females show differential developmental trajectories and responses to stress. It is likely that sex-dependent organization of neural circuits during the fetal period influences differential vulnerability to mental health problems. We consider in this review evidence that sexually dimorphic responses to early life stress are linked to two developmental disorders: affective problems (greater female prevalence) and autism spectrum disorder (greater male prevalence). Recent prospective studies illustrating the neurodevelopmental consequences of fetal exposure to stress and stress hormones for males and females are considered here. Plausible biological mechanisms including the role of the sexually differentiated placenta are discussed. (C) 2014 Elsevier Ltd. All rights reserved.

Despite its global relevance, our understanding of how influenza A virus transmission impacts the overall population dynamics of this RNA virus remains incomplete. To define this dynamic, we inserted neutral barcodes into the influenza A virus genome to generate a population of viruses that can be individually tracked during transmission events. We find that physiological bottlenecks differ dramatically based on the infection route and level of adaptation required for efficient replication. Strong genetic pressures are responsible for bottlenecks during adaptation across different host species, whereas transmission between susceptible hosts results in bottlenecks that are not genetically driven and occur at the level of the recipient. Additionally, the infection route significantly influences the bottleneck stringency, with aerosol transmission imposing greater selection than direct contact. These transmission constraints have implications in understanding the global migration of virus populations and provide a clearer perspective on the emergence of pandemic strains.

The HIV-1 Gag protein orchestrates all steps of virion genesis, including membrane targeting and RNA recruitment into virions. Using crosslinking-immunoprecipitation (CLIP) sequencing, we uncover several dramatic changes in the RNA-binding properties of Gag that occur during virion genesis, coincident with membrane binding, multimerization, and proteolytic maturation. Prior to assembly, and after virion assembly and maturation, the nucleocapsid domain of Gag preferentially binds to psi and Rev Response elements in the viral genome, and GU-rich mRNA sequences. However, during virion genesis, this specificity transiently changes in a manner that facilitates genome packaging; nucleocapsid binds to many sites on the HIV-1 genome and to mRNA sequences with a HIV-1-like, A-rich nucleotide composition. Additionally, we find that the matrix domain of Gag binds almost exclusively to specific tRNAs in the cytosol, and this association regulates Gag binding to cellular membranes.

Different alcohol drinking patterns, involving either small and frequent drinking bouts or large and long-lasting bouts, are found to differentially affect the risk for developing alcohol-related diseases, suggesting that they have different underlying mechanisms. Such mechanisms may involve orexigenic peptides known to stimulate alcohol intake through their actions in the hypothalamic paraventricular nucleus (PVN). These include orexin (OX), which is expressed in the perifornical lateral hypothalamus, and galanin (GAL) and enkephalin (ENK), which are expressed within as well as outside the PVN. To investigate the possibility that these peptides affect different aspects of consumption, a microstructural analysis of ethanol drinking behavior was performed in male, Sprague Dawley rats trained to drink 7% ethanol and implanted with guide shafts aimed at the PVN. While housed in specialized cages containing computerized intake monitors (BioDAQ Laboratory Intake Monitoring System, Research Diets Inc., New Brunswick, NJ) that measure bouts of ethanol drinking, these rats were given PVN injections of OX (0.9 nmol), GAL (1.0 nmol), or the ENK analog D-Ala2-met-enkephalinamide (DALA) (14.2 nmol), as compared to saline vehicle. Results revealed clear differences between the effects of these peptides. While all 3 stimulated ethanol intake, they had distinct effects on patterns of drinking, with OX increasing the number of drinking bouts, GAL increasing the size of the drinking bouts, and DALA increasing both the size and duration of the bouts. In contrast, these peptides had little impact on water or food intake. These results support the idea that different peptides can increase ethanol consumption by promoting distinct aspects of the ethanol drinking response. The stimulatory effect of OX on drinking frequency may be related to its neuronally stimulatory properties, while the stimulatory effect of GAL and ENK on bout size and duration may reflect a suppressive effect of these neuronally inhibitory peptides on the satiety-controlling PVN. (C) 2014 Elsevier Inc. All rights reserved.

We present a review of central exclusive dijet production in (p) over barp collisions, where the proton and antiproton emerge intact, and only two jets of transverse energy above a certain threshold are present in the final state. The results are published in two papers by the Collider Detector at Fermilab (CDF) Collaboration, a PRL (2000) and a PRD (2008), based on data collected at root s = 1.8 TeV and 1.96 TeV, respectively, and a D0 Collaboration paper from studies at 1.96 TeV. In all three cases predictions for the cross-section of Higgs boson production are discussed, a process that proceeds via a similar mechanism as dijet production. Roman Pot Spectrometers equipped with tracking detectors are used to measure the outgoing antiproton (CDF and D0) and proton (D0), and special forward detectors are employed to help reduce backgrounds and enrich the data in diffractive and exclusive dijet events.