[Molecular biology of SV 40, polyomavirus and adenovirus].
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Adenoviridae↗
Biomedical subjects
M Satake
Publications and source records attributed to M Satake.
Conotoxin GIIIA: selective inhibition of 22Na influx via voltage-dependent Na channels in adrenal medullary cells.
Conotoxin GIIIA and GIIIB from the marine snail Conus geographus have been reported to inhibit voltage-dependent Na channels in skeletal muscle and postganglionic sympathetic neuron, but have no effect on Na channels in brain, giant axon and heart. In eel electroplax, conotoxins were also shown to share the common binding sites with saxitoxin (see review Gray et al. 1988). In bovine adrenal medullary cells, conotoxin GIIIA inhibited veratridine-induced influx of 22Na, 45Ca and secretion of catecholamines with an IC50 of 6 mumols/l while saxitoxin suppressed veratridine-induced responses with an IC50 of 6.3 nmol/l. [3H]Saxitoxin binding to the cells was inhibited by unlabeled saxitoxin with an IC50 of 5.1 nmol/l, but was slightly reduced by 10 mumols/l conotoxin GIIIA. Conotoxin GIIIA, at 10 mumols/l, did not alter carbachol-induced influx of 22Na, 45CA and secretion of catecholamines as well as high K-induced 45Ca influx and catecholamine secretion. These results indicate that conotoxin GIIIA, at concentrations 950 fold higher than saxitoxin, inhibits Na influx via voltage-dependent Na channels, but has no effect on the nicotinic receptor-ion channel complex or the voltage-dependent Ca channels. Conotoxin GIIIA seems to bind at the sites which are distinct from saxitoxin, but are functionally linked to the voltage-dependent Na channels. Conotoxins may be useful for the classification of Na channels in excitable cell membranes.
Adrenal Medulla↗
Column chromatographic pre-concentration of iron(III) in alloys and biological samples with 1-nitroso-2-naphthol-3,6-disulphonate and benzyldimethyltetradecylammonium-perchlorate adsorbent supported on naphthalene using atomic absorption spectrometry.
The solid ion-pair material produced from the reaction between benzyldimethyltetradecylammonium chloride (BDTA) and sodium perchlorate on naphthalene provides the basis for a simple, rapid and selective technique for pre-concentrating iron from up to 500 ml of aqueous solution. Iron reacts with disodium 1-nitroso-2-naphthol-3,6-disulphonate (Nitroso-R salt) to form a water-soluble coloured chelate anion. The iron chelate anion forms a water-insoluble, stable iron-Nitroso-R-BDTA complex on naphthalene packed in a column. Trace amounts of iron are quantitatively retained on naphthalene in the pH range 3.5-7.5 and at a flow-rate of 1-2 ml min-1. The solid mass is dissolved out from the column with 5 ml of N,N-dimethylformamide and iron is determined by means of an atomic absorption spectrometer at 248 nm. The calibration graph is linear for concentrations of iron over the range of 0.5-20 micrograms in 5 ml of final solution. The standard deviation and relative standard deviation were calculated. The detection limit of the method was 0.0196 micrograms ml-1 of iron. The sensitivity for 1% absorption was 0.072 microgram ml-1 (0.165 microgram ml-1 by direct atomic absorption spectrometry of aqueous solution). The proposed method was applied to the determination of iron in standard alloys and biological samples.
Adsorption↗
Differentiation of F9 embryonal carcinoma cells induced by the c-jun and activated c-Ha-ras oncogenes.
The activated c-Ha-ras oncogene induced AP1-site DNA-binding activity in F9 cells. This induction appeared to be due, at least in part, to the induction of c-jun transcription. Both activated c-Ha-ras and c-jun induced the differentiation of F9 cells to endoderm-like cells. Thus, AP1 appears to play a key role in the initial stage of F9 cell differentiation.
Animals↗
Purification of a mouse nuclear factor that binds to both the A and B cores of the polyomavirus enhancer.
We have previously identified a protein factor, PEBP2 (polyomavirus enhancer-binding protein), in the nuclear extract from mouse NIH 3T3 cells which binds to the sequence motif, PEA2, located within the polyomavirus enhancer A element. Upon cellular transformation with activated oncogene c-Ha-ras, this factor frequently undergoes drastic molecular modifications into an altered form having a considerably reduced molecular size. In this study, the altered form, PEBP3, was purified to near homogeneity. The purified PEBP3 comprised two sets of families of polypeptides, alpha-1 to alpha-4 and beta-1 to beta-2, which were 30 to 35 kilodaltons and 20 to 25 kilodaltons in size, respectively. Both kinds of polypeptides possessed DNA-binding activities with exactly the same sequence specificity. Individual alpha or beta polypeptides complexed with DNA showed faster gel mobilities than did PEBP3. However, the original gel retardation pattern was restored when alpha and beta polypeptides were mixed together in any arbitrary pair. These observation along with the results of UV- and chemical-cross-linking studies led us to conclude that PEBP3 is a heterodimer of alpha and beta subunits, potentially having a divalent DNA-binding activity. Furthermore, PEBP3 was found to bind a second, hitherto-unnoticed site of the polyomavirus enhancer that is located within the B element and coincides with the sequence previously known as the simian virus 40 enhancer core homology. From comparison of this and the original binding sites, the consensus sequence for PEBP3 was defined to be PuACCPuCA. These findings provided new insights into the biological significance of PEBP3 and PEBP2.
Animals↗
A polyomavirus enhancer-binding protein, PEBP5, responsive to 12-O-tetradecanoylphorbol-13-acetate but distinct from AP-1.
Element I, homologous to the adenovirus type 5 E1A enhancer core, is a 10-bp sequence in the A core of the polyomavirus enhancer and was shown previously to be responsive to 12-O-tetradecanoylphorbol-13-acetate (TPA). We found that element I by itself was capable of activating polyomavirus DNA replication in COP-5 cells which express the polyomavirus large T antigen. A nuclear factor, polyomavirus enhancer-binding protein 5 (PEBP5), which bound to the entire sequence of element I and was responsive to TPA was identified by an in vitro binding assay. Although the binding site of PEBP5 partly overlaps with that of PEBP1 (PEA1), a member of the AP-1 family, PEBP5 appears to be a distinct factor. Since we previously showed that element I alone was able to activate transcription, our present results suggest that PEBP5 is involved in the regulation of both transcription and replication of DNA. The amount of PEBP5 increased after F9 cells were induced to differentiate by retinoic acid. A relatively large amount of PEBP5 was detected in lymphoid and trophoblast cells.
Animals↗
[Daily Japanese cedar pollen forecast in Sendai].
The forecast of daily Japanese cedar (Cryptomeria japonica) pollen counts was performed in Sendai in 1987, 1988 and 1989. The expected daily maximum temperature was used as a main determinative factor, and the term "pollen index", which is a ratio of a daily pollen count to the rest of the total seasonal pollen count, was devised and proved to be closely related to the daily maximum temperature. In 1987 and 1989, the total seasonal pollen count was very low, and daily pollen counts were in the lowest of three grades, except for a few days of the middle grade. In 1988, a fairly large number of pollen grains were observed, and forecasts of low grade were made for 28 days, middle grade for 25 days and high grade for 10 days, respectively. On the other hand, the actual daily pollen counts of low grade were 36 days, middle grade, 15 days, and high grade, 12 days, respectively. The accuracy of the forecast was 67% in 1988. The reasons for errors and the assignments for the forecast were discussed.
Forecasting↗
A ubiquitous repressor interacting with an F9 cell-specific silencer and its functional suppression by differentiated cell-specific positive factors.
A mutant of polyomavirus, F9-5000, capable of growing in F9 cell [M. Vasseur et al., J. Virol., 43: 800-808, 1982 (1)], has a deletion in the enhancer from nucleotide 5119 to nucleotide 5142. The oligonucleotide corresponding to the deleted region (delta F9-5000 element) showed silencer activity on gene expression in F9 cells. Mobility shift assay revealed a nuclear factor, PEBP4, in F9 nuclear extract which bound to the delta F9-5000 element. Mutations introduced into the PEBP4 binding site specifically abolished its binding as well as the inhibitory effect on gene expression. After F9 cells were induced to differentiate, two more factors, PEBP2 and PEBP1, a member of AP1 family, became detectable in addition to PEBP4, and at the same time the delta F9-5000 element lost silencer activity and acquired an enhancer activity. The recognition sequence of PEBP2 as well as that of PEBP1 overlapped with that of a repressor, PEBP4. PEBP4 and PEBP3, a factor related to PEBP2, were shown to compete for binding to delta F9-5000. Interplay of a ubiquitous negative factor and differentiation-induced positive factors may represent one aspect of the gene regulation during embryonic development.
Animals↗
A tumor promoting phorbol ester, TPA, enhances polyomavirus DNA replication by activating the function of the viral enhancer.
The effect of tumor promoter, 12-O-tetradecanoylphorbol 13-acetate (TPA) on enhancer dependent polyomavirus (Py) DNA replication was examined in cells expressing Py large T antigen. The results showed that TPA enhanced Py DNA replication by stimulating the activity of the A element, one of the two cores of Py enhancer. Of the three subdomains of the A element, the biding sites of PEBP1 (PEA1), a member of AP1 family, and of PEBP5 were by themselves able to activate Py DNA replication. Furthermore, each binding site of PEBP1 and PEBP5 responded to TPA to enhance Py DNA replication. The results suggest that growth promoting signals could activate DNA replication directly via enhancer binding proteins.
Antigens, Polyomavirus Transforming↗
[Nucleotide metabolism in remnant rat liver after major hepatic resection].
Major hepatic resection is restricted in the presence of cirrhosis, because the cirrhotic liver is less able to regenerate. In the present study, to clarify what factors play a major role as inhibitors of the regeneration process, we focused on the changes in liver purine nucleotides and their catabolite levels in rats with cirrhosis. Decreases in adenine nucleotides and guanine nucleotides were observed after resection both in normal and thioacetamide-induced cirrhotic livers. These were prolonged in rats with cirrhosis. Tissue levels of hypoxanthine and xanthine increased both in the control group and in the cirrhotic group. The increase in xanthine level was remarkable in the cirrhotic group compared with the control group. These results indicate that xanthine oxidase activity is increased in cirrhotic liver after major hepatic resection. Xanthine oxidase catalyzes the oxidation of hypoxanthine to xanthine and xanthine to uric acid. Xanthine and uric acid are end metabolites of purine nucleotides. On the other hand, superoxide is generated in association with this reaction. Therefore, the disturbance in the energy metabolism and the increase in superoxide formation which are caused by the activation of xanthine oxidase might be involved in the regeneration process as inhibitory factors in cirrhotic rat liver.
Animals↗
Structure of phosphonoglycosphingolipid containing pyruvylated galactose in nerve fibers of Aplysia kurodai.
A phosphonoglycosphingolipid, designated as FGL-IIb, was identified in nerve fibers of Aplysia kurodai by two-dimensional thin layer chromatography (Abe, S., Araki, S., and Satake, M. (1986) Biomed. Res. (Tokyo) 7, 47-51). FGL-IIb was isolated from the nervous system of A. kurodai by Iatrobeads column chromatography using three solvent systems. Pyruvic acid was identified by thin layer chromatography as its 2,4-dinitrophenylhydrazone and established by permethylation studies to be attached as a ketal to O-3 and O-4 of the terminal galactose of the oligosaccharide chain in FGL-IIb. By sugar analysis, permethylation studies, fast atom bombardment-mass spectrometry, and proton magnetic resonance spectrometry, the structure of FGL-IIb was concluded to be [3,4-O-(1-carboxyethylidene)]Gal beta 1----3GalNAc alpha 1----3(Fuc alpha 1----2) (2-aminoethylphosphonyl----6)Gal beta 1----4Glc beta 1----1ceramide. Its major aliphatic components were palmitic acid, octadeca-4-sphingenine and anteisononadeca-4-sphingenine. This is the first report of the occurrence of pyruvylated galactose as a constituent of animal sphingolipid.
Acidic Glycosphingolipids↗
Abolishment of c-fos inducibility in ras-transformed mouse osteoblast cell lines.
Proto-oncogene c-fos is induced by many types of cellular stimuli, such as 12-O-tetradecanoylphorbol-13-acetate (TPA), epidermal growth factor (EGF), serum (fetal bovine), calcium ionophore A23187, and dibutyryl cAMP (But2cAMP). In this study, c-fos induction was abolished in ras-transformed mouse osteoblast cells (MC3T3). Transformants of MC3T3 were isolated after transfection with Ki or Ha murine sarcoma virus DNA. All Ki- or Ha-ras transformed MC3T3 clones examined showed exceedingly low levels of c-fos induction by all inducers, as determined by the change in amounts of c-fos mRNA or its product. Induction of other TPA-responsive genes, such as metallothionein, was not altered in some ras-transformed cells; c-myc and c-jun expression was constitutively high in all the ras-transformed clones. Nuclear extracts and gel shift assay showed that the binding activity to c-fos enhancer element (serum response element) was altered in ras-transformed cells. These results indicate that transformation with ras oncogene induces modification of c-fos enhancer binding factors and that this modification is one cause for the decrease in c-fos induction.
Animals↗
Phosphorylation of neurofilament proteins and localization of axonal swellings in motor neuron disease.
Seven lumbosacral spinal cords with motor neuron disease were examined immunocytochemically with monoclonal antibodies (MAb) directed against neurofilament proteins (NFP). Each of the 5 MAbs used in this study was monospecific to one of the triplet of NFP. Two of them were specific to the highly phosphorylated form of high molecular weight peptide of NFP (NFP-H). All 5 MAbs stained all axonal swellings examined. In 2 spinal cords examined, some axonal swellings were found in the anterolateral funiculus and some of these were as far as 1000 microns from the grey matter. This localization of axonal swellings suggests that a high degree of phosphorylation of NFP is not the cause of accumulation of NFP in axonal swellings in motor neuron disease.
Adult↗
Comparative monolayer investigations of surface properties of negatively charged glycosphingolipids from vertebrates (gangliosides) and invertebrates (SGL-II, lipid IV).
The surface properties of four negatively charged glycosphingolipids from vertebrates, the sialo-glycosphingolipids (= gangliosides) GM1, GD1a, GT1b and a sulfo-glycosphingolipid (= sulfatide), and of the two negatively charged glycosphingolipids from lower invertebrates, the glucurono-glycosphingolipid Lipid IV and the aminophosphono-glycosphingolipid SGL-II were investigated in monolayers at the air/water interface. The molecular peculiarities under investigation were surface pressure (pi) and surface potential (delta V) which are described for Lipid IV and SGL-II for the first time. The surface pressure/area isotherms of all glycosphingolipids were typical of a liquid-expanded monolayer and, with the exception of SGL-II, exhibited a phase transition to a liquid-condensed state at surface pressures above 20 mN/m. The surface potential/molecular area data found for gangliosides in the closely packed state at pi = 30 mN/m (GM1: delta V = -17 mV; GD1a: delta V = -35 mV; GT1b: delta V = -39 mV) showed only a slight influence of the additional number of negatively charged residues. For Lipid IV, the surface behavior was very similar to GM1 both possessing one negative group per molecule, whereas in SGL-II also the surface potential data (delta V = +173 mV) were different compared with GD1a both possessing two negative groups per molecule. The addition of Ca2+ condensed the monolayers of all glycolipids and increased the potential in the direction to more positive values, but these findings were less effective in SGL-II films. On the basis of monolayer results presented here, in biological membranes of invertebrates especially Lipid IV might play a similar role as the ganglioside GM1 in vertebrate cells.
Acidic Glycosphingolipids↗
Characterization of phosphonoglycosphingolipids containing pyruvate: localization in Aplysia nerve bundles.
A phosphonoglycosphingolipid, designated as FGL-IIb, was first identified in nerve fibers of Aplysia kurodai by two-dimensional TLC (Abe, S. et al. (1986) Biomed. Res. 7, 47-51), and its chemical structure has been determined to be 3,4-O-(1-carboxyethylidene)]Gal beta 1----3GalNac alpha 1----3(Fuc alpha 1----2)(2-aminoethylphosphonyl----6)Gal beta 1----4Glc beta 1----1ceramide (Araki, S. et al., submitted). Cryostat and paraffin sections of the nervous tissue and skin of Aplysia were examined immunohistochemically with antiserum against FGL-IIb. With this antiserum, only nerve bundles were stained distinctly: nerve cells in ganglia and in subcutaneous and muscular tissues and other cell elements were not stained. From histochemical findings in cryostat sections pretreated with chloroform-methanol (2 : 1, v/v) and from the results of Western blot analysis of the nervous tissue, the staining was concluded to be due to glycolipid antigens. The antiserum reacted with FGL-IIb and other phosphonoglycosphingolipids named FGL-I, FGL-IIa, FGL-V, and F-9 on TLC plates. This reactivity of FGL-IIb was abolished by mild acid-methanol treatment, and the lost reactivity was recovered by alkaline hydrolysis. These findings suggest that the free carboxyl group of the pyruvic acid of FGL-IIb is essential for the immunological reaction and that all the glycolipids listed above have the same epitope as that of FGL-IIb. Immunohistochemical findings indicated that these glycolipids including FGL-IIb are localized specifically in nerve bundles of Aplysia.
Acidic Glycosphingolipids↗
Two overlapping sequence motifs within the polyomavirus enhancer are independently the targets of stimulation by both the tumor promoter 12-O-tetradecanoylphorbol-13-acetate and the Ha-ras oncogene.
A tumor-promoting phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA), strongly stimulates the activity of polyomavirus enhancer in a human erythroleukemia cell line, K562. The target of stimulation was the previously defined A element (from nucleotides 5107 to 5130) of the enhancer. We found that within the A element, two partly overlapping sequence motifs (one from nucleotides 5107 to 5117, the other from nucleotides 5113 to 5121) were independently the targets of TPA stimulation. The former is homologous to the enhancer core sequence of the adenovirus type 5 E1A gene, and the latter shares the consensus AP-1-binding site. In addition, transiently expressed Ha-ras oncogene also stimulated these two subelements in K562 cells, as we reported for NIH 3T3 cells previously.
Animals↗
Loss of responsiveness of an AP1-related factor, PEBP1, to 12-O-tetradecanoylphorbol-13-acetate after transformation of NIH 3T3 cells by the Ha-ras oncogene.
The function of the A element (nucleotides 5107 to 5130) of the polyomavirus enhancer is augumented in NIH 3T3 cells by a tumor-promoting phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA). One of its targets is an AP1 consensus sequence motif recognized by a nuclear factor, PEBP1. In Ha-ras-transformed NIH 3T3 cells, however, A element function was not enhanced by TPA treatment, and at the same time PEBP1 was not detected in the nuclear extract by a mobility shift assay. PEBP1 was not detected in either the extract from NIH 3T3 cells treated in vivo with a protein kinase inhibitor, staurosporine, or the extract from NIH 3T3 cells after treatment in vitro with phosphatase. These results suggest that PEBP1 is required to be properly phosphorylated for DNA binding and that it is underphosphorylated, possibly due to the downregulation of protein kinase C in Ha-ras-transformed cells. In addition, we observed that PEBP2, which bound to the A element adjacent to PEBP1, was converted to apparently related PEBP3 when conditions favored underphosphorylation.
Animals↗
Biological properties of angiotensin-converting enzyme inhibitor derived from tuna muscle.
A novel inhibitor of angiotensin-converting enzyme (ACE) derived from tuna muscle, Pro-Thr-His-Ile-Lys-Trp-Gly-Asp (tuna AI), was chemically synthesized, and its biological properties were investigated. Synthetic tuna AI was found to be chemically and biologically indistinguishable from the native one. Tuna AI inhibited rabbit lung ACE non-competitively with Ki values of 1.7 and 5.7 microM with substrates, hippuryl-L-histidyl-L-leucine and angiotensin I, respectively. This peptide (5.3 microM) also doubled the effect of bradykinin in the contraction of isolated guinea pig ileum. The peptide did not show zinc chelating activity and carboxypeptidase A inhibitory activity. Thus, tuna AI was found to be a unique ACE inhibitory peptide with non-competitive manner, differing from many naturally occurring peptide ACE-inhibitors.
Amino Acid Sequence↗