Phosphorylation of a nucleolus-specific phosphoprotein in vitro.

The cellular site and characteristics of the phosphorylation of a nucleolus-specific phosphoprotein (molecular weight, 120 000) in mouse ascites tumor cells were studied. The phosphoprotein was strongly labeled with ³²P when the isolated nucleoli were incubated with [γ-³²P]ATP in vitro. This phosphoprotein, and protein kinase for the protein phosphorylation were both purified from 0.3 M KCl soluble protein fraction of the nucleoli by hydroxylapatite and phosphocellulose column chromatographies. It was found that phosphorylation of the nucleolus-specific phosphoprotein was catalyzed selectively by a guanosine 3:5-monophosphate-dependent protein kinase in the nucleoli and the reaction product was the same phosphoprotein as the substrate used.     

Relationship between enhancement of morphine analgesia and inhibition of enkephalinase by 2S, 3R 3-amino-2-hydroxy-4-phenylbutanoic acid derivatives

The effects of nineteen AHPA* derivatives were examined on morphine analgesia by tail-flick test in rats and on enkephalinase inhibition which was based on the formation of tyrosyl-glycyl-glycine from met-enkephalin. The correlation between the enhancement of morphine analgesia in vivo and enkephalinase inhibition in vitro was analyzed. The different analogs varied considerably in the degree of enhancement of morphine analgesia and inhibition of enkephalinase. A close relationship between enkephalinase inhibition expressed by IC50 in vitro and enhancement of morphine analgesia in vivo was observed in thirteen out of nineteen AHPA derivatives examined. One of other six AHPA derivatives which showed weak effectiveness in potentiating on morphine analgesia but was highly potent as an enkephalinase inhibitor, caused potent analgesic action when it was applied intracisternally indicating poor penetration of the blood brain barrier. The possibility was discussed that some of other compounds excluded from the linear relationship might act on other enkephalin degrading enzymes such as aminopeptidase.     

Interaction of basic oligo-L-amino acids with deoxyribonucleic acids. Oligo-L-arginines of various chain lengths and herring sperm DNA

The interaction of DNA and oligo-L-arginines having definite chain lengths of 1-17 residues was studied by precipitate formation and thermal denaturation of the complexes in order to obtain a better understanding of the roles of nuclear basic proteins. The results can be summarized as follows. 1. Those oligo-L-arginines, (Arg)n, in which n greater than or larger than 4 can bind with DNA irreversibly to form precipitates of the complexes. Among them, oligomers larger than (Arg)5 precipitate DNA completely in Arg/P input ratios below 1. The Arg/P ratios in the precipitates are between 0.6-0.8. 2. The thermal stability of the complexes depends on the method of complex formation, and complexes formed by the dialysis method are more stable than those formed by the mixing method. 3. The binding of (Arg)n to DNA was found to be reversible and in a equilibrium for n less than or equal to 6. In general, the longer the oligomer, the higher the stability of the complex at a definite Arg/P ratio. 4. For (Arg)7-10, three kinds of complexes with different stabilities are formed between DNA and oligopeptides. 5. For (Arg)14-17, only a restricted type of complexes can be formed between DNA and oligomers, as in the case with poly-L-arginine or protamines. 6. The interaction between basic nuclear proteins and DNA is discussed in the light of the basic region in protamine and histone molecules.     

The crystal structure of di-D-fructose anhydride III,produced by inulin D-fructotransferase

Reaction of methyl α-d-glucopyranoside and methyl α-d-mannopyranoside with alkaline hydrogen peroxide and a ferrous salt, at room temperature and below, afforded the corresponding d-glycosiduronic acids. On dehydration, the acids gave the corresponding gamma lactones, with a shift of the pyranoid ring to a furanoid ring. Surprisingly, the glycosidic methyl group was retained during the oxidation reactions and pyranose-furanose interconversions. This retention is rationalized by a mechanism involving formation of a pseudo-acyclic intermediate. Another unexpected reaction was the conversion of slightly moist methyl d-glucopyranosiduronolactone syrup, on standing for 5–6 days at room temperature, into crystalline d-glucofuranurono-6,3-lactone, and of methyl α-d-mannopyranosidurono-6,3-lactone into crystalline d-mannofuranurono-6,3-lactone.     

Production of anti-self-H-2 antibodies by C3D2F1 mice hyperimmune to L cell/L1210 hybrids and L1210 leukemia cells

During the course of immunization of (C3H × DBA/2)F₁ mice (genotype H-2^k/b) with L cell (H-2^k/k)/L1210 leukemia cell (H-2^d/d) hybrids and L1210 leukemia cells, some of them produced a good titer of anti-self-H-2 (H-2^d) antibodies. Antigens recognized by this anti-self-H-2 antiserum were shown to be controlled by the H-2K-IA-IB-IJ-IE subregions of the H-2^d but not H-2^k nor H-2^b haplotypes of parental as well as F₁ origins and to have a tissue distribution identical to that of class 1 H-2 (H-2K/D) antigens.     

Recombinant bovine neurokinin-2 receptor stably expressed in Chinese hamster ovary cells couples to multiple signal transduction pathways.

Neurokinins are a family of neuropeptides with widespread distribution mediating a broad spectrum of physiological actions through three distinct receptor subtypes: NK-1, NK-2, and NK-3. We investigated some of the second messenger and cellular processes under control by the recombinant bovine NK-2 receptor stably expressed in Chinese hamster ovary cells. In this system the NK-2 receptor displays its expected pharmacological characteristics, and the physiological agonist neurokinin A stimulates several cellular responses. These include 1) transient inositol 1,4,5-trisphosphate (IP3) formation and Ca2+ mobilization, 2) increased out put of arachidonic acid and prostaglandin E2 (PGE2), 3) enhanced cyclic AMP (cAMP) generation, 4) increased de novo DNA synthesis, and 5) an induction of the "immediate early" genes c-fos and c-jun. Although NK-2 receptor-mediated IP3 formation involves activation of a pertussis toxin-insensitive G-protein, increased cAMP production is largely a secondary response and can be at least partially attributed to autocrine stimulation by endogenously generated eicosanoids, particularly PGE2. This is the first demonstration that a single recombinant neurokinin receptor subtype can regulate, either directly or indirectly, multiple signal transduction pathways and suggests several potential important mediators of neurokinin actions under physiological conditions.     

A simple method for the release of asparagine-linked oligosaccharides from a glycoprotein purified by SDS-polyacrylamide gel electrophoresis.

A simple method for the release of oligosaccharides from glycoproteins separated by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) has been developed. Asialo-alpha 1-acid glycoprotein, which was tritiated at the nonreducing terminal D-galactopyranosyl residue by reduction with sodium borotritide after incubation with D-galactose oxidase, was used as a model compound. After electrophoretic separation of the glycoprotein, oligosaccharides were released by the use of a gas-phase hydrazinolysis apparatus. In the first method, the gel was stained with Coomassie Blue and the glycoprotein together with the gel was directly subjected to gas-phase hydrazinolysis after removal of water in a P2O5 desiccator. The recovery of released oligosaccharides was 25.9 +/- 2.4%, based on the amount of the glycoprotein loaded on the gel within the range of 3.5-28.5 micrograms. In the second method, the glycoprotein was electroblotted onto an Immobilon transfer membrane and was visualized by staining with Coomassie Blue. A small piece of the membrane with the corresponding band was cut out, dried in a desiccator and subjected to gas-phase hydrazinolysis. In this case, the recovery of released oligosaccharides was 15.2 +/- 1.0%. These procedures, particularly the first one, should be widely applicable for the isolation of oligosaccharides from glycoproteins separated by SDS-PAGE.     

Biological activity of a proteoglycan form of macrophage colony-stimulating factor and its binding to type V collagen.

Two different types of macrophage colony-stimulating factors (M-CSF) were found, one with an apparent molecular mass of 85 kDa and the other greater than 200 kDa. The high molecular mass M-CSF was identified as a proteoglycan carrying chondroitin sulfate glycosaminoglycan and was designated as the proteoglycan form of M-CSF (PG-M-CSF). In this study, we compared the biological activity of the 85-kDa M-CSF and PG-M-CSF and examined the binding properties of these two M-CSF to certain extracellular matrix proteins, i.e. types I-V collagen and fibronectin, using a modified enzyme-linked immunosorbent assay. PG-M-CSF was capable of supporting the formation of murine macrophage colonies, and pretreatment of PG-M-CSF with chondroitinase AC, which degrades chondroitin sulfate, did not alter its colony-stimulating activity. The specific activity of PG-M-CSF was similar to that of the 85-kDa M-CSF. The 85-kDa M-CSF had no apparent affinity for the extracellular matrix proteins examined, whereas PG-M-CSF had an appreciable binding capacity to type V collagen, but did not bind to types I, II, III, and IV collagen or to fibronectin. Pretreatment of PG-M-CSF with chondroitinase AC completely abolished the binding of the species to type V collagen. Addition of exogenous chondroitin sulfate inhibited the binding of PG-M-CSF to type V collagen in a dose-dependent manner. These data indicated that the interaction between PG-M-CSF and type V collagen was mediated by the chondroitin sulfate chain of PG-M-CSF. PG-M-CSF bound to type V collagen could stimulate the proliferation of bone marrow macrophages, indicating that the matrix protein-bound PG-M-CSF retained its biological activity. This interaction between PG-M-CSF and type V collagen implies that the role of PG-M-CSF may be distinct from that of 85-kDa M-CSF.     

Identification of a high molecular weight macrophage colony-stimulating factor as a glycosaminoglycan-containing species.

Chinese hamster ovary cells transfected with a 4.0-kilobase macrophage colony-stimulating factor (M-CSF) cDNA express two different M-CSF species; one has an apparent molecular weight of 85,000 and is identified as a homodimer of a 43-kDa subunit, and the other has an indeterminate structure greater than 200 kDa. In this study, we investigated the structure of the high molecular weight M-CSF by immunochemical procedures. The high molecular weight M-CSF was easily purified, since it bound tightly to DEAE-Sephacel and eluted at a characteristically high salt concentration. The high molecular weight M-CSF migrated as a diffuse band of over than 200,000 on nonreducing sodium dodecyl sulfate-polyacrylamide gels. Analysis of the same samples under reducing conditions revealed that the larger species consisted of a heteromer of the 43- and 150-200-kDa M-CSF subunits. Digestion of the 150-200-kDa M-CSF subunit with chondroitinase, which degrades the chondroitin sulfate glycosaminoglycan chain, yielded a 100 kDa band. This species was secreted instead of 150-200-kDa species when the cells were cultured in the presence of beta-D-xyloside, which inhibits the elongation of the chondroitin sulfate glycosaminoglycan chain in proteoglycans, providing additional evidence for the existence of a chondroitin sulfate chain in the 150-200-kDa M-CSF subunit. Removal of O- and N-linked carbohydrate from the 150-200-kDa subunit yielded a polypeptide chain with a larger molecular mass (approximately 45 kDa) than that of the 43-kDa subunit (approximately 25 kDa). Collectively, these results indicate that the 150-200-kDa M-CSF subunit is a proteoglycan with a core protein that may be an alternatively processed form of M-CSF.