Herpes simplex virus type 1 glycoprotein C-negative mutants exhibit multiple phenotypes, including secretion of truncated glycoproteins

A virus-neutralizing monoclonal antibody specific for glycoprotein C (gC) of herpes simplex virus type 1 strain KOS was used to select a number of neutralization-resistant mutants. A total of 103 of these mutants also were resistant to neutralization by a pool of gC-specific antibodies and thus were operationally defined as gC-. Analysis of mutant-infected cell mRNA showed that a 2.7-kilobase mRNA, comparable in size to the wild-type gC mRNA, was produced by nearly all mutants. However, six mutants, gC-5, gC-13, gC-21, gC-39, gC-46, and gC-98, did not produce the normal-size gC mRNA but rather synthesized a novel 1.1-kilobase RNA species. These mutants had deletions of 1.6 kilobases in the coding sequence of the gC structural gene, which explains their gC- phenotype. Despite the production of an apparently normal mRNA by the remaining 97 mutants, only 7 mutants produced a detectable gC polypeptide. In contrast to wild-type gC, which is a membrane-bound glycoprotein with an apparent molecular weight of 130,000 (130K), five of these mutants quantitatively secreted proteins of lower molecular weight into the culture medium. These were synLD70 (101K), gC-8 (109K), gC-49 (112K), gC-53 (108K), and gC-85 (106K). The mutant gC-3 secreted a protein that was indistinguishable in molecular weight from wild-type KOS gC. Another mutant, gC-44, produced a gC protein which also was indistinguishable from wild-type gC by molecular weight and which remained cell associated. Pulse-labeling of infected cells in the presence and absence of the glycosylation inhibitor tunicamycin demonstrated that these proteins were glycosylated and provided estimates of the molecular weights of the nonglycosylated primary translation products. The smallest of these proteins was produced by synLD70 and was 48K, about two-thirds the size of the wild-type polypeptide precursor (73K). Physical mapping of the mutations in synLD70 and gC-8 by marker rescue placed these mutations in the middle third of the gC coding sequence. Mapping of the mutations in other gC- mutants, including two in which no protein product was detected, also placed these mutations within or very close to the gC gene. The biochemical and genetic data available on mutants secreting gC gene products suggest that secretion is due to the lack of a functional transmembrane anchor sequence on these mutant glycoproteins.     

Herpes simplex virus type 1 DNA cleavage and encapsidation require the product of the UL28 gene: isolation and characterization of two UL28 deletion mutants.

The herpes simplex virus type 1 UL28 gene contains a 785-amino-acid open reading frame that codes for an essential protein. Studies with temperature-sensitive mutants which map to the UL28 gene indicate that the UL28 gene product (ICP18.5) is required for packaging of viral DNA and for expression of viral glycoproteins on the surface of infected cells (C. Addison, F. J. Rixon, and V. G. Preston, J. Gen. Virol. 71:2377-2384, 1990; B. A. Pancake, D. P. Aschman, and P. A. Schaffer, J. Virol. 47:568-585, 1983). In this study, we describe the isolation of two UL28 deletion mutants that were constructed and propagated in Vero cells transformed with the UL28 gene. The mutants, gCB and gC delta 7B, contained deletions of 1,881 and 537 bp, respectively, in the UL28 gene. Although the mutants synthesize viral DNA, they fail to form plaques or produce infectious virus in cells that do not express the UL28 gene. Transmission electron microscopy and Southern blot analysis demonstrated that both mutants are defective in cleavage and encapsidation of viral DNA. Analysis by cell surface immunofluorescence showed that the UL28 gene is not required for expression of viral glycoproteins on the surface of infected cells. A rabbit polyclonal antiserum was made against an Escherichia coli-expressed Cro-UL28 fusion protein. This antibody reacted with an infected-cell protein having an apparent molecular mass of 87 kDa. The 87-kDa protein was first detected at 6 h postinfection and was expressed as late as 24 h postinfection. No detectable UL28 protein was synthesized in gCB- or gC delta 7B-infected Vero cells.     

Hexon-only binding of VP26 reflects differences between the hexon and penton conformations of VP5, the major capsid protein of herpes simplex virus.

VP26 is a 12-kDa capsid protein of herpes simplex virus 1. Although VP26 is dispensable for assembly, the native capsid (a T=16 icosahedron) contains 900 copies: six on each of the 150 hexons of VP5 (149 kDa) but none on the 12 VP5 pentons at its vertices. We have investigated this interaction by expressing VP26 in Escherichia coli and studying the properties of the purified protein in solution and its binding to capsids. Circular dichroism spectroscopy reveals that the conformation of purified VP26 consists mainly of beta-sheets (approximately 80%), with a small alpha-helical component (approximately 15%). Its state of association was determined by analytical ultracentrifugation to be a reversible monomer-dimer equilibrium, with a dissociation constant of approximately 2 x 10(-5) M. Bacterially expressed VP26 binds to capsids in the normal amount, as determined by quantitative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Cryoelectron microscopy shows that the protein occupies its usual sites on hexons but does not bind to pentons, even when available in 100-fold molar excess. Quasi-equivalence requires that penton VP5 must differ in conformation from hexon VP5: our data show that in mature capsids, this difference is sufficiently pronounced to abrogate its ability to bind VP26.     

Phospholipid turnover and ultrastructural correlates during spontaneous germinal vesicle breakdown of the bovine oocyte: effects of a cyclic AMP phosphodiesterase inhibitor.

The turnover of [32P]orthophosphate in bovine oocyte phospholipids was studied during the early stages of spontaneous meiotic maturation, and during inhibition of this process by the cAMP phosphodiesterase inhibitor 3-isobutyl-1-methyl-xanthine (IBMX). Radioactive lipids were separated by TLC and the meiotic stage was determined cytogenetically. Ultrastructure of the nuclear membrane was examined using transmission EM. During the commitment period to meiotic resumption, which precedes germinal vesicle breakdown (GVBD), small localized convolutions appeared in the intact nuclear membrane. This was accompanied by a decrease in [32P]phosphatidic acid (PA) and an increase in [32P]-phosphatidylcholine (PC). This was followed by extensive convolutions, and subsequent dissociation, of the nuclear membrane, concomitant with a tremendous surge in [32P]PC and [32P]phosphatidylethanolamine (PE). The cAMP-mediated maintenance of meiotic arrest involved retention of entire nuclear envelope integrity and total inhibition of the surge in [32P]PC and [32P]PE which accompanied GVBD. The increase in [32P]phosphatidylinositol (PI) associated with all stages of early meiotic resumption was unaffected by IBMX. Microinjection of heparin inhibited GVBD, and injection of inositol 1,4,5-trisphosphate (IP3) overrode IBMX-maintained meiotic arrest in almost 40% of the oocytes. The results suggest that there may be several functions for phospholipid turnover in the regulation of spontaneous meiotic resumption in the bovine oocyte. The first precedes the commitment period, and involves IP3 generation to serve as the primary signal for meiotic resumption. The second occurs concomitant with the commitment period, is unaffected by the level of intracellular cAMP, and is associated with the general turnover of phospholipid. The third is associated with GVBD, and is cAMP-sensitive, and may represent stimulation of de novo synthesis of phospholipid, thereby permitting disruption of the nuclear membrane.     

Transmembrane adaptor protein WBP1L regulates CXCR4 signalling and murine haematopoiesis

WW domain binding protein 1‐like (WBP1L), also known as outcome predictor of acute leukaemia 1 (OPAL1), is a transmembrane adaptor protein, expression of which correlates with ETV6‐RUNX1 (t(12;21)(p13;q22)) translocation and favourable prognosis in childhood leukaemia. It has a broad expression pattern in haematopoietic and in non‐haematopoietic cells. However, its physiological function has been unknown. Here, we show that WBP1L negatively regulates signalling through a critical chemokine receptor CXCR4 in multiple leucocyte subsets and cell lines. We also show that WBP1L interacts with NEDD4‐family ubiquitin ligases and regulates CXCR4 ubiquitination and expression. Moreover, analysis of Wbp1l‐deficient mice revealed alterations in B cell development and enhanced efficiency of bone marrow cell transplantation. Collectively, our data show that WBP1L is a novel regulator of CXCR4 signalling and haematopoiesis.     

Thermodynamic of Water Sorption of Grape Seed: Temperature Effect of Sorption Isotherms and Thermodynamic Characteristics

After determination of sorption isotherms of grape seeds using gravimetric method, five models with temperature effect were used to fit water sorption isotherms of grape seeds to investigate temperature effect on sorption isotherms and its thermodynamic characteristics. Halsey model had minimum mean relative percentage error (M _e ) and all other models used were good in fitting experimental data (with M _e of less than 10 %). Differential parameters such as net isosteric heat, isosteric heat, differential entropy and integral function such as equilibrium heat, net equilibrium heat, integral entropy and surface potential have been calculated. The net isosteric heat, isosteric heat and differential entropy decreased with moisture content. The net equilibrium enthalpy, equilibrium enthalpy and integral entropy decreased with moisture content. The surface potential at four temperatures (35, 45, 55 and 65 °C) was estimated, and low temperature effect was reported.     

Paced QRS morphology predicts incident left ventricular systolic dysfunction and atrial fibrillation

Background

The prognostic significance of paced QRS complex morphology on surface ECG remains unclear. This study aimed to assess long-term outcomes associated with variations in the paced QRS complex.

MicroRNA replacement therapy in cancer

Despite the recent progress in cancer management approaches, the mortality rate of cancer is still growing and there are lots of challenges in the clinics in terms of novel therapeutics. MicroRNAs (miRNA) are regulatory small noncoding RNAs and are already confirmed to have a great role in regulating gene expression level by targeting multiple molecules that affect cell physiology and disease development. Recently, miRNAs have been introduced as promising therapeutic targets for cancer treatment. Regulatory potential of tumor suppressor miRNAs, which enables regulation of entire signaling networks within the cells, makes them an interesting option for developing cancer therapeutics. In this regard, over recent decades, scientists have aimed at developing powerful and safe targeting approaches to restore these suppressive miRNAs in cancerous cells. The present review summarizes the function of miRNAs in tumor development and presents recent findings on how miRNAs have served as therapeutic agents against cancer, with a special focus on tumor suppressor miRNAs (mimics). Moreover, the latest investigations on the therapeutic strategies of miRNA delivery have been presented.