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Biomedical subjects

R Devlin

Publications and source records attributed to R Devlin.

At least 37 records · Page 2Linked to original sources
PubMed1990

Frameshift mutation in exon 3 of the lipoprotein lipase gene causes a premature stop codon and lipoprotein lipase deficiency.

Several mutations in the human lipoprotein lipase (LPL) gene have been shown to underlie LPL deficiency. These mutations occur in patients who are mainly of European descent, and comprise a single base transition causing a premature stop codon, four separate amino acid substitutions and two large gene rearrangements. Together they account for approximately 40% of the LPL alleles in a cohort of 50 patients whose DNA has been examined in this laboratory. We now report on a new mutation in exon 3 of the LPL gene from a South African subject of South-east Asian extraction. This mutation comprises a six base-pair insertion at the site of a single base deletion. The net insertion of five base-pairs at amino acid positions 102 to 103 causes a shift in the reading frame, generating 44 amino acid residues of random sequence and a premature stop codon within exon 4. This mutation is predicted to result in the synthesis of a markedly truncated protein and is the cause of the enzyme deficiency in our patient.

Adult↗
PubMed1989

Identification of mRNA coding for factor VII protein in human alveolar macrophages--coagulant expression may be limited due to deficient postribosomal processing.

Clotting factors synthesized by monocytes and macrophages may initiate coagulation reactions during inflammation. Functional vitamin K-dependent coagulation factors have been found to be associated with human monocytes/macrophages, but there are no reports identifying mRNA coding for vitamin K-dependent proteins in these cells. In the present studies, factor VII mRNA was found in total RNA extracted from freshly isolated human alveolar macrophages using hybridization with a complementary DNA probe. On the other hand, vitamin K-dependent carboxylase activity which is required for postribosomal modification of the protein, was not detectable in the macrophages before or after culture, and human blood mononuclear leukocytes also lacked this enzyme activity. Control human and rat hepatoma cells exhibited high levels of carboxylase activity within the same experiments. Using sensitive kinetic assays, no increase in factor VII activity was detected during culture of alveolar macrophages under conditions promoting 1.78 +/- .24 (n = 8) fold increases of tissue factor activity. These findings with freshly isolated cells demonstrate that alveolar macrophages synthesize factor VII mRNA in vivo. However, the mRNA was found in the absence of evidence for gamma-carboxylase activity or processing of the factor into a functional clotting enzyme. The results imply that functional expression of any synthesized coagulation factor VII in alveolar macrophages may be limited or prevented due to a cellular deficiency at the level of postribosomal processing.

Carbon-Carbon Ligases↗
PubMed1986

Analysis of tropomyosin cDNAs isolated from skeletal and smooth muscle mRNA.

Several clones containing alpha tropomyosin sequences were isolated from cDNA libraries prepared from quail skeletal or smooth muscle RNA. All of these clones contain identical sequences coding for amino acids 81-257 of alpha skeletal muscle tropomyosin where they overlap, strongly indicating they are derived from the same gene. However, there are differences among these clones in sequences coding for the final 27 amino acids, as well as 3' untranslated sequences. In addition, S1 nuclease and Northern analyses indicate that coding sequences at the 5' end of the tropomyosin mRNA are also differentially expressed in smooth and skeletal muscle. These data point to the likelihood that differential splicing at both the 5' and 3' ends of a single tropomyosin gene results in the appearance of multiple tissue-specific transcripts.

Amino Acid Sequence↗
PubMed1985

Changes in synthesis of concanavalin A binding proteins during nerve cell differentiation.

Changes in the synthesis of concanavalin A binding proteins were analyzed at various times during nerve cell differentiation. Both mouse neuroblastoma cells as well as primary cells isolated from chicken dorsal root ganglia were used in these studies. Conditions were optimized for the biochemical differentiation of these cells, which were pulsed with radioactive methionine at several times during differentiation. Soluble extracts were prepared and optimum conditions for the isolation of those proteins which bind the lectin concanavalin A were determined. Incorporation of radioactivity into specific concanavalin A binding proteins was analyzed by two-dimensional gel electrophoresis and by computerized densitometry of the autoradiographs. Our results show that 10 concanavalin binding proteins are made only in differentiating neuroblastoma cells, and that twelve such proteins are made only in differentiating dorsal root ganglia cells. In addition, the synthesis of several other concanavalin A binding proteins increases dramatically during nerve cell differentiation. This class of proteins is now being further characterized by biochemical and immunological techniques.

Animals↗