Genetic and physical mapping of the biglycan gene on the mouse X Chromosome

A human cDNA for biglycan (BGN) has recently been mapped to proximal Xq28. We have mapped the murine locus, Bgn, approximately 50 kb distal to DXPas8, using a combination of genetic mapping in an interspecific backcross of B6CBA-A ^w-J/A-Bpa x Mus spretus and physical mapping using pulsed field gel electrophoresis and analysis of murine yeast artificial chromosomes (YACs) containing both DXPas8 and Bgn. Our mapping studies also appear to exclude Bgn as a candidate gene for the bare patches (Bpa) mutation and for the homologous human disorder X-linked dominant chondrodysplasia punctata (CDPX2).     

Disruption of the Ran System by Cysteine Oxidation of the Nucleotide Exchange Factor RCC1

Transport regulation by the Ran GTPase requires its nuclear localization and GTP loading by the chromatin-associated exchange factor RCC1. These reactions generate Ran protein and Ran nucleotide gradients between the nucleus and the cytoplasm. Cellular stress disrupts the Ran gradients, but the specific mechanisms underlying this disruption have not been elucidated. We used biochemical approaches to determine how oxidative stress disrupts the Ran system. RCC1 exchange activity was reduced by diamide-induced oxidative stress and restored with dithiothreitol. Using mass spectrometry, we found that multiple solvent-exposed cysteines in RCC1 are oxidized in cells treated with diamide. The cysteines oxidized in RCC1 included Cys93, which is solvent exposed and unique because it becomes buried upon contact with Ran. A Cys93Ser substitution dramatically reduced exchange activity through an effect on RCC1 binding to RanGDP. Diamide treatment reduced the size of the mobile fraction of RCC1-green fluorescent protein in cells and inhibited nuclear import in digitonin-permeabilized cell assays. The Ran protein gradient was also disrupted by UV-induced stress but without affecting RCC1 exchange activity. Our data suggest that stress can disrupt the Ran gradients through RCC1-dependent and RCC1-independent mechanisms, possibly dependent on the particular stress condition.     

Inhibition of exogenous RNA-dependent protein synthesis by a low-molecular-weight RNA from nuclear ribonucleoprotein particles of adenovirus-infected HeLa cells

Low-molecular-weight RNA (4S to > 5.5S) isolated from nuclear ribonucleo-protein particles of adenovirus-infected HeLa cells inhibited cell-free protein synthesis directed by polyribosomal RNA from rabbit reticulocytes by more than 80%. In a reconstituted system inhibitory RNA did not prevent the binding of Met-tRNA_f-GTP-IF ternary complex to 40S subunits; however, it repressed the formation of 80S from 40S-mRNA complex and 60S subunits. In binding assays in which authentic IF-M2A and IF-M2B were present, the inhibitor competed with messenger molecules for binding site(s) in IF-M2B. The inhibitory RNA appears to be a 5.5S RNA.     

Characterization of the antigen recognized by monoclonal antibody 1D3

Human ovarian mucinous cystadenocarcinoma-associated antigen recognized by murine monoclonal antibody 1D3 (Bhattacharya et al., 1982) was characterized. Gel filtration and sodium dodecylsulfate polyacrylamide gel electrophoresis, followed by Western-blot analysis showed that 1D3 is a high molecular weight glycoprotein. Isoelectric focusing of 1D3 antigen showed 2 overlapping antigenic components with PI 2.5 and 2.6. 1D3 antigen was extremely stable (10 min at 100 degrees C) to heating. The antigenic activity was slightly stimulated by treatment with galactosidases, but neuraminidase treatment enhanced the antigenic activity about 3-fold. Antigen activity was completely stable to periodate oxidation. Pronase and trypsin treatment completely destroyed the antigenic activity. Properties of 1D3 antigen suggest that this is a high molecular weight (approximately 5-20 x 10(6) Dalton), sialomucin. Monoclonal antibody 1D3 recognizes only the protein part of this molecule.     

Bioprospection of anti-inflammatory phytochemicals suggests rutaecarpine and quinine as promising 15-lipoxygenase inhibitors

15-Lipoxygenase (15-LOX) belongs to the family of nonheme iron containing enzymes that catalyzes the peroxidation of polyunsaturated fatty acids (PUFAs) to generate eicosanoids that play an important role in signaling pathways. The role of 15-LOX has been demonstrated in atherosclerosis as well as other inflammatory diseases. In the present study, drug-like compounds were first screened from a set of anti-inflammatory phytochemicals based on Lipinski's rule of five (ROF) and in silico toxicity filters. Two lead compounds-quinine (QUIN) and rutaecarpine (RUT) were shortlisted by analyzing molecular interactions and binding energies of the filtered compounds with the target using molecular docking. Molecular dynamics simulation studies indicate stable trajectories of apo_15-LOX and docked complexes (15-LOX_QUIN and 15-LOX_RUT). In vitro 15-LOX inhibition studies shows that both QUIN and RUT have lower inhibitory concentration (IC₅₀) value than the control (quercetin). Both QUIN and RUT exhibit moderate antioxidant activities. The cell viability study of these compounds suggests no significant toxicity in HEK-293 cell lines. Further, QUIN and RUT both did not show any inhibition against selected Gram-positive and Gram-negative bacterial species. Thus, based on our present findings, rutaecarpine and quinine may be suggested as promising 15-LOX inhibitor for the prevention of the atherosclerosis development.     

Ectopic expression of olfactory receptors and associated G-protein subunits in the head integument of the amphihaline migratory fish hilsa Tenualosa ilisha

The chemosensory nature of the tissue from the dorsal surface of the head (also termed sensory pad; SP) of the amphihaline diadromous fish hilsa Tenualosa ilisha was investigated for odorant receptor (OR), olfactory marker protein (OMP) and G-protein subunits (Gαs-olf, Gαq, Gαo, Gαi3) through immunolocalization and immunoblotting techniques. The immunolocalization of OR, OMP and G-protein subunits showed clear expression of these proteins in the tissues of the SP. Robust expressions of these proteins in the SP were detected with immunoblot analysis. The strong expression of these proteins in the SP indicates that the tissues from this area in riverine T. ilisha may play significant role in chemosensing and signalling through ectopic expression of olfactory receptor proteins which are otherwise reported in olfactory organs in vertebrates. Being migratory in nature, ectopic expression of these receptors in T. ilisha probably helps them to prevent damage to epidermal tissues of the SP, or they may also utilize them as a chemo and mechanosensory tool to optimize chemo-communications during migration.