Regulated nucleocytoplasmic trafficking of viral gene products: a therapeutic target?

The study of viral proteins and host cell factors that interact with them has represented an invaluable contribution to understanding of the physiology as well as associated pathology of key eukaryotic cell processes such as cell cycle regulation, signal transduction and transformation. Similarly, knowledge of nucleocytoplasmic transport is based largely on pioneering studies performed on viral proteins that enabled the first sequences responsible for the facilitated transport through the nuclear pore to be identified. The study of viral proteins has also enabled the discovery of several nucleocytoplasmic regulatory mechanisms, the best characterized being through phosphorylation. Recent delineation of the mechanisms whereby phosphorylation regulates nuclear import and export of key viral gene products encoded by important human pathogens such as human cytomegalovirus dengue virus and respiratory syncytial virus has implications for the development of antiviral therapeutics. In particular, the development of specific and effective kinase inhibitors makes the idea of blocking viral infection by inhibiting the phosphorylation-dependent regulation of viral gene product nuclear transport a real possibility. Additionally, examination of a chicken anemia virus (CAV) protein able to target selectively into the nucleus of tumor but not normal cells, as specifically regulated by phosphorylation, opens the exciting possibility of cancer cell-specific nuclear targeting. The study of nucleoplasmic transport may thus enable the development not only of new antiviral approaches, but also contribute to anti-cancer strategies.     

Involvement of Lysophosphatidic Acid,Sphingosine 1-Phosphate and Ceramide 1-Phosphate in the Metabolization of Phosphatidic Acid by Lipid Phosphate Phosphatases in Bovine Rod Outer Segments

The aim of the present research was to evaluate the generation of [2-3H]diacylglycerol ([2-3H]DAG) from [2-3H]-Phosphatidic acid ([2-3H]PA) by lipid phosphate phosphatases (LPPs) at different concentrations of lysophosphatidic acid (LPA), sphingosine 1-phosphate (S1P), and ceramide 1-phosphate (C1P) in purified ROS obtained from dark-adapted retinas (DROS) or light-adapted retinas (BLROS) as well as in ROS membrane preparations depleted of soluble and peripheral proteins. Western blot analysis revealed the presence of LPP3 exclusively in all membrane preparations. Immunoblots of entire ROS and depleted ROS did not show dark-light differences in LPP3 levels. LPPs activities were diminished by 53% in BLROS with respect to DROS. The major competitive effect on PA hydrolysis was exerted by LPA and S1P in DROS and by C1P in BLROS. LPPs activities in depleted ROS were similar to the activity observed in entire DROS and BLROS, respectively. LPA, S1P and C1P competed at different extent in depleted DROS and BLROS. Sphingosine and ceramide inhibited LPPs activities in entire and depleted DROS. Ceramide also inhibited LPPs activities in entire and in depleted BLROS. Our findings are indicative of a different degree of competition between PA and LPA, S1P and C1P by LPPs depending on the illumination state of the retina.     

Seawater requirement for the production of lipoxazolidinones by marine actinomycete strain NPS8920

A novel marine actinomycete strain NPS8920 produces a new class of 4-oxazolidinone antibiotics lipoxazolidinone A, B and C. Lipoxazolidinone A possesses good potency (1-2 microg/mL) against drug-resistant pathogens methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VRE). Strain NPS8920 exhibits different morphologies in both agar and submerged cultures. The ability of strain NPS8920 to sporulate on saline-based agar media but not on deionized water-based agar medium supported that strain NPS8920 is a marine actinomycete. While strain NPS8920 does not require seawater for growth, the production of lipoxazolidinones by strain NPS8920 can only be detected in the seawater-based media. The optimal production of lipoxazolidinones was observed in the natural seawater-based medium. Strain NPS8920 produced 10-20% of lipoxazolidinones in the synthetic sea salt Instant Ocean-based medium and no production in the sodium chloride-based and deionized water-based media.     

Trace Element Status of Chronic Renal Patients Undergoing Hemodialysis

The purpose of this study was to examine the status of trace elements (Cu, Zn, and Fe) and minerals (Mg, K, Na, and Cl) and the level of biochemical parameters (urea, creatinine, total protein, albumin, and glucose) in hemodialysis (HD) patients. This study included 30 HD patients (25 men and 5 women) aged 52.12 +/- 3.13 years and 30 healthy subjects (23 men and 7 women) aged 51.64 +/- 2.22 years. This study investigated the status of trace elements and minerals in HD patients. It was found that the total HD patients (before and after dialysis) had statistically lower Zn and albumin in the after-dialysis group K and Cl levels and higher Mg, creatinine, and urea in the before-dialysis group K and in the after-dialysis group glucose levels than those of the controls. It was determined that the results might be helpful in monitoring patients with renal failure in terms of insufficiency or excess of trace elements and minerals. There was positive correlation for Mg-K (r = 0.64; p = 0.001), creatinine-urea (r = 0.59; p = 0.001), K-urea (r = 0.56; p = 0.001), K-creatinine (r = 0.52; p = 0.003), Mg-creatinine (r = 0.47; p = 0.008), Zn-albumin (r = 0.40; p = 0.028), and Zn-creatinine (r = 0.40; p = 0.031) in the before-dialysis session. There was also positive correlation for creatinine-urea (r = 0.56; p = 0.001), K-urea (r = 0.39; p = 0.035), and Mg-creatinine (r = 0.38; p = 0.041) in the after-analysis session. As a result of the analysis of regression between serum levels of albumin and zinc in total HD patients, the use of the level of albumin might be a suitable choice in determining zinc deficiency resulting from the decrease in the level of zinc in parallel to that of albumin. The results also suggest that the relationship between creatinine and K, Mg, and Zn could be ascribed to the loss of renal function.     

Localization of laminin α3B chain in vascular and epithelial basement membranes of normal human tissues and its down-regulation in skin cancers

The basement membrane (BM) proteins laminins, which consist of alpha, beta and gamma chains, play critical roles in the maintenance of tissue structures. One of laminin alpha chains, alpha3 has two isoforms, the truncated form alpha3A and the full-sized form alpha3B. In contrast to alpha3A laminins, little is known about alpha3B laminins. To show the histological distribution of the laminin alpha3B chain, we prepared alpha3B-specific monoclonal antibodies. Immunohistochemical analysis showed that the alpha3B chain was colocalized with the alpha3A, beta3 and gamma2 chains in the epithelial BMs of the skin, esophagus, breast and lung, suggesting the presence of laminin-3B32 (laminin-5B) and laminin-3A32 (laminin-5A). In the lung alveoli, laminin-3B32 was dominant over laminin-3A32, but vice versa in other epithelial BMs. In contrast, the BMs of blood vessels including capillaries were strongly positive for alpha3B, but almost or completely negative for alpha3A, beta3 and gamma2. alpha3B was colocalized with beta1 and gamma1 in these BMs. The alpha3B chain was scarcely detected in the vessels of malignant skin cancers, though the gamma2 and beta3 chains were highly expressed in the cancer cells. These results strongly suggest that the laminin alpha3B chain is widely expressed in vascular BMs of normal tissues, probably as laminin-3B11/3B21 (laminin-6B/7B).     

A perivascular origin for mesenchymal stem cells in multiple human organs

Mesenchymal stem cells (MSCs), the archetypal multipotent progenitor cells derived in cultures of developed organs, are of unknown identity and native distribution. We have prospectively identified perivascular cells, principally pericytes, in multiple human organs including skeletal muscle, pancreas, adipose tissue, and placenta, on CD146, NG2, and PDGF-Rbeta expression and absence of hematopoietic, endothelial, and myogenic cell markers. Perivascular cells purified from skeletal muscle or nonmuscle tissues were myogenic in culture and in vivo. Irrespective of their tissue origin, long-term cultured perivascular cells retained myogenicity; exhibited at the clonal level osteogenic, chondrogenic, and adipogenic potentials; expressed MSC markers; and migrated in a culture model of chemotaxis. Expression of MSC markers was also detected at the surface of native, noncultured perivascular cells. Thus, blood vessel walls harbor a reserve of progenitor cells that may be integral to the origin of the elusive MSCs and other related adult stem cells.     

eQTL Viewer: visualizing how sequence variation affects genome-wide transcription

Background  

Expression Quantitative Trait Locus (eQTL) mapping methods have been used to identify the genetic basis of gene expression variations. To map eQTL, thousands of expression profiles are related with sequence polymorphisms across the genome through their correlated variations. These eQTL distribute in many chromosomal regions, each of which can include many genes. The large number of mapping results produced makes it difficult to consider simultaneously the relationships between multiple genomic regions and multiple expressional profiles. There is a need for informative bioinformatics tools to assist the visualization and interpretation of these mapping results.     

A focused antibody library for selecting scFvs expressed at high levels in the cytoplasm

Background  

Intrabodies are defined as antibody molecules which are ectopically expressed inside the cell. Such intrabodies can be used to visualize or inhibit the targeted antigen in living cells. However, most antibody fragments cannot be used as intrabodies because they do not fold under the reducing conditions of the cell cytosol and nucleus.     

Mapping phosphoproteins in <Emphasis Type="Italic">Mycoplasma genitalium</Emphasis> and <Emphasis Type="Italic">Mycoplasma pneumoniae</Emphasis>

Background  

Little is known regarding the extent or targets of phosphorylation in mycoplasmas, yet in many other bacterial species phosphorylation is known to play an important role in signaling and regulation of cellular processes. To determine the prevalence of phosphorylation in mycoplasmas, we examined the CHAPS-soluble protein fractions of Mycoplasma genitalium and Mycoplasma pneumoniae by two-dimensional gel electrophoresis (2-DE), using a combination of Pro-Q Diamond phosphoprotein stain and ³³P labeling. Protein spots that were positive for phosphorylation were identified by peptide mass fingerprinting using MALDI-TOF-TOF mass spectrometry.