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R J Magee

Publications and source records attributed to R J Magee.

7 recordsLinked to original sources
PubMed1999

Mutational analysis of a heterogeneous nuclear ribonucleoprotein A2 response element for RNA trafficking.

Cytoplasmic transport and localization of mRNA has been reported for a range of oocytes and somatic cells. The heterogeneous nuclear ribonucleoprotein (hnRNP) A2 response element (A2RE) is a 21-nucleotide segment of the myelin basic protein mRNA that is necessary and sufficient for cytoplasmic transport of this message in oligodendrocytes. The predominant A2RE-binding protein in rat brain has previously been identified as hnRNP A2. Here we report that an 11-nucleotide subsegment of the A2RE (A2RE11) was as effective as the full-length A2RE in binding hnRNP A2 and mediating transport of heterologous RNA in oligodendrocytes. Point mutations of the A2RE11 that eliminated binding to hnRNP A2 also markedly reduced the ability of these oligoribonucleotides to support RNA transport. Oligodendrocytes treated with antisense oligonucleotides directed against the translation start site of hnRNP A2 had reduced levels of this protein and disrupted transport of microinjected myelin basic protein RNA. Several A2RE-like sequences from localized neuronal RNAs also bound hnRNP A2 and promoted RNA transport in oligodendrocytes. These data demonstrate the specificity of A2RE recognition by hnRNP A2, provide direct evidence for the involvement of hnRNP A2 in cytoplasmic RNA transport, and suggest that this protein may interact with a wide variety of localized messages that possess A2RE-like sequences.

Animals↗
PubMed1990

Interactions of a molybdenum(VI) oxo-cation with some uronic acids: a 1H- and 13C-nuclear magnetic resonance study.

The interactions of molybdate, [MoO4]2- with some uronic acids in aqueous D2O solution were studied by 1H- and 13C-NMR. Evidence is presented for a specific binding site of an Mo(VI) oxo-cation (Mo2O5(2+] with alpha-,beta-D-glucuronic acid. It is proposed that complexation involves the carboxylate oxygen (O-6b) and O-4 of the hydroxyl oxygen in a pyranose form (4C1), in the pH region 3.5-5.8.

Carbon Isotopes↗
PubMed1989

Inhibition of oxidative phosphorylation by organotin thiocarbamates.

A series of triphenyl-, tricyclohexyl- and tribenzyltin compounds have been synthesized and examined as inhibitors of mitochondrial oxidative phosphorylation. All compounds tested inhibit oxidative phosphorylation linked to succinate oxidation by potato tuber mitochondria. All of the organotin compounds inhibit ADP-stimulated O2 uptake linked to succinate oxidation with concentrations for 50% inhibition in the range 2-50 microM. This inhibition is not due to inhibition of electron transport from succinate to O2 per se: none of the organotin compounds at 50 microM substantially inhibit the rate of succinate oxidation in the presence of 2,4-dinitrophenol. Representative organotin compounds at 0.5-50 microM do not act as uncouplers of succinate oxidation. It is concluded that the organotin compounds act as energy transfer inhibitors to inhibit oxidative phosphorylation in potato tuber mitochondria. A similar mode of action of representative organotin compounds was found with rat liver mitochondria. These organotin compounds inhibit a hydrophobic Ca2+-dependent plant protein kinase in the absence but not in the presence of thiols.

Animals↗
PubMed1978

Naturally-occurring heavy metal binding protein in invertebrates.

Low molecular weight cadmium, copper, and zinc binding protein has been isolated from the mussel Mytilus edulis in the cadmium polluted areas of Corio Bay adjacent to Melbourne. Its molecular weight and other properties suggest that it belongs to the metallothionein family of metal binding proteins. Its synthesis may have been induced in the cyctoplasmic solutions of the cells as a regulatory mechanism to avoid intoxication by excess uptake of any of the metals.

Animals↗