The rockefeller university

Tetherin encodes an interferon-inducible antiviral protein that traps a broad spectrum of enveloped viruses at infected cell surfaces. Despite the absence of any clearly related gene or activity, we describe possible scenarios by which tetherin arose that exemplify how protein modularity, evolvability, and robustness can create and preserve new functions. We find that tetherin genes in various organisms exhibit no sequence similarity and share only a common architecture and location in modern genomes. Moreover, tetherin is part of a cluster of three potential sister genes encoding proteins of similar architecture, some variants of which exhibit antiviral activity while others can be endowed with antiviral activity by a simple modification. Only in slowly evolving species (e.g., coelacanths) does tetherin exhibit sequence similarity to one potential sister gene. Neofunctionalization, drift, and genetic conflict appear to have driven a near complete loss of sequence similarity among modern tetherin genes and their sister genes.

The decorrelation in the azimuthal angle between the most forward and the most backward jets (Mueller-Navelet jets) is measured in data collected in pp collisions with the CMS detector at the LHC at root s = 7 TeV. The measurement is presented in the form of distributions of azimuthal-angle differences, Delta phi, between the Mueller-Navelet jets, the average cosines of (pi - Delta phi), 2(pi - Delta phi), and 3(pi - Delta phi), and ratios of these cosines. The jets are required to have transverse momenta, p(T), in excess of 35 GeV and rapidities, |y|, of less than 4.7. The results are presented as a function of the rapidity separation, Delta y, between the Mueller-Navelet jets, reaching Delta y up to 9.4 for the first time. The results are compared to predictions of various Monte Carlo event generators and to analytical predictions based on the DGLAP and BFKL parton evolution schemes.

Understanding how membrane nanoscale organization controls transmembrane receptors signaling activity remains a challenge. We studied interferon-gamma receptor (IFN-gamma R) signaling in fibroblasts from homozygous patients with a T168N mutation in IFNGR2. By adding a neo-N-glycan on IFN-gamma R2 subunit, this mutation blocks IFN-gamma activity by unknown mechanisms. We show that the lateral diffusion of IFN-gamma R2 is confined by sphingolipid/cholesterol nanodomains. In contrast, the IFN-gamma R2 T168N mutant diffusion is confined by distinct actin nanodomains where conformational changes required for Janus-activated tyrosine kinase/signal transducer and activator of transcription (JAK/STAT) activation by IFN-gamma could not occur. Removing IFN-gamma R2 T168N-bound galectins restored lateral diffusion in lipid nanodomains and JAK/STAT signaling in patient cells, whereas adding galectins impaired these processes in control cells. These experiments prove the critical role of dynamic receptor interactions with actin and lipid nanodomains and reveal a new function for receptor glycosylation and galectins. Our study establishes the physiological relevance of membrane nanodomains in the control of transmembrane receptor signaling in vivo.

Background The relationship between intervertebral disc degeneration and chronic infection by Propionibacterium acnes is controversial with contradictory evidence available in the literature. Previous studies investigating these relationships were under-powered and fraught with methodical differences; moreover, they have not taken into consideration P. acnes' ability to form biofilms or attempted to quantitate the bioburden with regard to determining bacterial counts/genome equivalents as criteria to differentiate true infection from contamination. The aim of this prospective cross-sectional study was to determine the prevalence of P. acnes in patients undergoing lumbar disc microdiscectomy. Methods and Findings The sample consisted of 290 adult patients undergoing lumbar microdiscectomy for symptomatic lumbar disc herniation. An intraoperative biopsy and pre-operative clinical data were taken in all cases. One biopsy fragment was homogenized and used for quantitative anaerobic culture and a second was frozen and used for real-time PCR-based quantification of P. acnes genomes. P. acnes was identified in 115 cases (40%), coagulase-negative staphylococci in 31 cases (11%) and alpha-hemolytic streptococci in 8 cases (3%). P. acnes counts ranged from 100 to 9000 CFU/ml with a median of 400 CFU/ml. The prevalence of intervertebral discs with abundant P. acnes (>= 1x10(3) CFU/ml) was 11% (39 cases). There was significant correlation between the bacterial counts obtained by culture and the number of P. acnes genomes detected by real-time PCR (r = 0.4363, p<0.0001). Conclusions In a large series of patients, the prevalence of discs with abundant P. acnes was 11%. We believe, disc tissue homogenization releases P. acnes from the biofilm so that they can then potentially be cultured, reducing the rate of false-negative cultures. Further, quantification study revealing significant bioburden based on both culture and real-time PCR minimize the likelihood that observed findings are due to contamination and supports the hypothesis P. acnes acts as a pathogen in these cases of degenerative disc disease.

Rationale: Endothelial Notch signaling is critical for early vascular development and survival. Yet, previously described mice lacking endothelial a disintegrin and metalloproteinase 10 (ADAM10), a key regulator of Notch signaling, survived into adulthood with organ-specific vascular defects. These findings raised questions about whether these vascular defects were related to Notch signaling or other functions of ADAM10. Objective: The aims of the study are to determine whether compensatory or redundant functions of ADAM17 in Notch signaling can explain the survival of Adam10 Delta EC mice, explore the contribution of different Tie2-Cre transgenes to the differences in survival, and establish whether the Adam10 Delta EC vascular phenotypes can he recapitulated by inactivation of Notch receptors in endothelial cells. Methods and Results: Mice lacking ADAM10 and ADAM17 in endothelial cells (Adam10/Adam17 Delta EC), which survived postnatally with organ-specific vascular defects, resembled Adam10 Delta EC mice. In contrast, Adam10 Delta EC mice generated with the Tie2Cre transgene previously used to inactivate endothelial Notch (Adam10 Delta ECFlv) died by E10.5. Quantitative polymerase chain reaction analysis demonstrated that Cre-mediated recombination occurs earlier in Adam10 Delta ECFlv mice than in the previously described Adam10 Delta EC mice. Finally, mice lacking endothelial Notchl (Notch1 Delta EC) share some organ-specific vascular defects with Adam10 Delta EC mice, whereas Notch4(-/-) mice lacking endothelial Notchl (Notch1 Delta EC/Notch4(-/-)) had defects in all vascular beds affected in Adam10 Delta EC mice. Conclusions: Our results argue against a major role for ADAM17 in endothelial Notch signaling and clarify the difference in phenotypes of previously described mice lacking ADAM10 or Notch in endothelial cells. Most notably, these findings uncover new roles for Notch signaling in the development of organ-specific vascular beds.

The impact of alpha linolenic acid (ALA), EPA, and DHA on obesity and metabolic complications was studied in mice fed a high-fat, high-sucrose (HF) diet. HF diets were supplemented with ALA, EPA, or DHA (1% w/w) and given to C57BL/6J mice for 16 weeks and to Ob/Ob mice for 6 weeks. In C57BL/6J mice, EPA reduced plasma cholesterol (-20%), limited fat mass accumulation (-23%) and adipose cell hypertrophy (-50%), and reduced plasma leptin concentration (-60%) compared with HF-fed mice. Furthermore, mice supplemented with EPA exhibited a higher insulin sensitivity (+24%) and glucose tolerance (+20%) compared with HF-fed mice. Similar effects were observed in EPA-supplemented Ob/Ob mice, although fat mass accumulation was not prevented. By contrast, in comparison with HF-fed mice, DHA did not prevent fat mass accumulation, increased plasma leptin concentration (+128%) in C57BL/6J mice, and did not improve glucose homeostasis in C57BL/6J and Ob/Ob mice. In 3T3-L1 adipocytes, DHA stimulated leptin expression whereas EPA induced adiponectin expression, suggesting that improved leptin/adiponectin balance may contribute to the protective effect of EPA.(jlr) In conclusion, supplementation with EPA, but not ALA and DHA, could preserve glucose homeostasis in an obesogenic environment and limit fat mass accumulation in the early stage of weight gain.-Pinel, A., E. Pitois, J-P. Rigaudiere, C. Jouve, S. De Saint-Vincent, B. Laillet, C. Montaurier, A. Huertas, B. Morio, and F. Capel. EPA prevents fat mass expansion and metabolic disturbances in mice fed with a Western diet.

While an essential role of HIV-1 integrase (IN) for integration of viral cDNA into human chromosome is established, studies with IN mutants and allosteric IN inhibitors (ALLINIs) have suggested that IN can also influence viral particle maturation. However, it has remained enigmatic as to how IN contributes to virion morphogenesis. Here, we demonstrate that IN directly binds the viral RNA genome in virions. These interactions have specificity, as IN exhibits distinct preference for select viral RNA structural elements. We show that IN substitutions that selectively impair its binding to viral RNA result in eccentric, non-infectious virions without affecting nucleocapsid-RNA interactions. Likewise, ALLINIs impair IN binding to viral RNA in virions of wildtype, but not escape mutant, virus. These results reveal an unexpected biological role of IN binding to the viral RNA genome during virion morphogenesis and elucidate the mode of action of ALLINIs.

In the family of protein arginine methyltransferases (PRMTs) that predominantly generate either asymmetric or symmetric dimethylarginine (SDMA), PRMT7 is unique in producing solely monomethylarginine (MMA) products. The type of methylation on histones and other proteins dictates changes in gene expression, and numerous studies have linked altered profiles of methyl marks with disease phenotypes. Given the importance of specific inhibitor development, it is crucial to understand the mechanisms by which PRMT product specificity is conferred. We have focused our attention on active-site residues of PRMT7 from the protozoan Trypanosoma brucei. We have designed 26 single and double mutations in the active site, including residues in the Glu-Xaa(8)-Glu (double E) loop and the Met-Gln-Trp sequence of the canonical Thr-His-Trp (THW) loop known to interact with the methyl-accepting substrate arginine. Analysis of the reaction products by high resolution cation exchange chromatography combined with the knowledge of PRMT crystal structures suggests a model where the size of two distinct subregions in the active site determines PRMT7 product specificity. A dual mutation of Glu-181 to Asp in the double E loop and Gln-329 to Ala in the canonical THW loop enables the enzyme to produce SDMA. Consistent with our model, the mutation of Cys-431 to His in the THW loop of human PRMT9 shifts its product specificity from SDMA toward MMA. Together with previous results, these findings provide a structural basis and a general model for product specificity in PRMTs, which will be useful for the rational design of specific PRMT inhibitors.

All retroviruses package cellular RNAs into virions. Studies of murine leukemia virus (MLV) revealed that the major host cell RNAs encapsidated by this simple retrovirus were LTR retrotransposons and noncoding RNAs (ncRNAs). Several classes of ncRNAs appeared to be packaged by MLV shortly after synthesis, as precursors to tRNAs, small nuclear RNAs, and small nucleolar RNAs were all enriched in virions. To determine the extent to which the human immunodeficiency virus (HIV-1) packages similar RNAs, we used high-throughput sequencing to characterize the RNAs within infectious HIV-1 virions produced in CEM-SS T lymphoblastoid cells. We report that the most abundant cellular RNAs in HIV-1 virions are 7SL RNA and transcripts from numerous divergent and truncated members of the long interspersed element (LINE) and short interspersed element (SINE) families of retrotransposons. We also detected precursors to several tRNAs and small nuclear RNAs as well as transcripts derived from the ribosomal DNA (rDNA) intergenic spacers. We show that packaging of a pre-tRNA requires the nuclear export receptor Exportin 5, indicating that HIV-1 recruits at least some newly made ncRNAs in the cytoplasm. Together, our work identifies the set of RNAs packaged by HIV-1 and reveals that early steps in HIV-1 assembly intersect with host cell ncRNA biogenesis pathways.

Polyamines play important roles in a range of cellular processes. In this issue of Cell Host & Microbe, Mounce et al. (2016) link polyamine metabolism to the interferon response and demonstrate proviral effects for polyamines. The study points to the pathway as a potential novel pan-viral therapeutic target.