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Biomedical subjects

O Smithies

Publications and source records attributed to O Smithies.

At least 181 records · Page 10Linked to original sources
PubMed1976

HLA membrane antigens: sequencing by intrinsic radioactivity.

Radiochemical sequence data are presented for the amino termini of mixed HLA antigens A1 and B8 isolated from a human lymphoblastoid cell line. Cells were labeled intrinsically in small-scale tissue culture with 14C-labeled amino acids and [14C]pyruvate. The specific activities obtained were sufficiently high and uniform to permit direct radiochemical sequencing of the antigens. HLA antigens were isolated by adsorption to a solid-phase anti-beta2-microglobulin immunoadsorbent followed by electrophoresis. The method should be generally applicable and useful for sequencing all parts of the molecule.

Amino Acid Sequence↗
PubMed1975

Low molecular weight urinary proteins. I. Partial amino acid sequences of the retinol-binding proteins of man and dog.

Human and dog retinol-binding proteins were isolated and their physico-chemical characteristics compared. Partial amino acid sequences of the first 50 residues were determined for both proteins and found to be remarkably similar. Only five residues were shown to be different; all could be due to single base pair mutations. However, immunological cross-reactivity was not detected between the two proteins with specific antisera prepared in rabbits against the human and dog retinol-binding proteins.

Amino Acids↗
PubMed1975

Hybridization of labeled RNA to DNA in agarose gels.

Specific DNA restriction endonuclease fragments can be identified after electrophoresis in agarose gels by hybridization in the gel (in situ) to radioactive homologous RNA. RNA-DNA hybrids are detected by autoradiography of the gel. Comparison of band patterns of the autoradiogram and the ethidium bromide stained gel allows the identification of the DNA fragment which is complementary to the RNA probe. The technique is rapid, easy and inexpensive. It is sensitive enough to detect individual genes in a mixture of fragments produced by restriction enzyme digestion of complex cellular DNA. We have used this technique to determine which of the Hin III and Eco R1 fragments of phi80d3ilv+su+7 and E. coli DNAs contain the 5S, 16S and 23S ribosomal RNA (rRNA) genes of E. coli.

DNA↗
PubMed1972

Initiation of protein synthesis at an unusual position in an immunoglobulin gene?

The amino acid sequence of urinary beta(2)-microglobulin has been partially determined and found to be related to the constant region of IgG immunoglobulin heavy chain. beta(2)-Microglobulin is present in normal individuals. Its gene may have evolved from an immunoglobulin gene by the use of an unusually located start signal for initiating synthesis of the polypeptide.

Amino Acid Sequence↗
PubMed1972

Dog homologue of human 2 -microglobulin.

The amino-acid sequence of human beta(2)-microglobulin, a protein of 100 residues, is related to parts of the constant region of IgG heavy chain. The dog homologue of human beta(2)-microglobulin has now been isolated and its amino-acid sequence has been partially determined. The two proteins (human and dog beta(2)-microglobulins) are demonstrably different at only 6 or 7 of the 42 positions examined. Use of the dog should permit experimental investigation of the functional relationships of beta(2)-microglobulin to immunoglobulins and the immune system. beta(2)-Microglobulin has also been detected in serum from a chimpanzee. The gene for beta(2)-microglobulin may correspond to the end portion of an immunoglobulin heavy chain gene.

Adult↗
PubMed1971

Deletions in immunoglobulin polypeptide chains as evidence for breakage and repair in DNA.

The partial sequence of the light chain of the myeloma-like immunoglobulin Sac shows a large deletion in its variable region. The sequence provides evidence that the corresponding gene was formed by the repair of DNA broken at nonhomologous positions. Data from other immunoglobulin (heavy) chains containing large deletions are compatible with their genes also being the result of DNA breakage and nonhomologous repair. Single homologous reciprocal exchanges in DNA networks at immunoglobulin loci could be the cause of the nonhomologous breaks. The relevance of these events to the generation of normal antibody variability remains to be determined.

Amino Acid Sequence↗
PubMed1970

Pathways through networks of branched DNA.

Differentiation may be controlled by forks in DNA each having a replicatable protein "switch," stable in either a "left" or a "right" configuration, which determines the path through the DNA network taken by RNA polymerases during transcription. The possibility for dedifferentiation exists, but differentiation could be made irreversible by the exertion of a similar control over parts of the paths through the network taken by DNA polymerases. The concept of bistable switches at DNA branch points can be used to account for antibody variability.

Antibodies↗