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Biomedical subjects

O Smithies

Publications and source records attributed to O Smithies.

At least 199 records · Page 11Linked to original sources
PubMed1968

Genetic polymorphism of C'3(beta1C-globulin) in human serum.

Genetic polymorphism of the third component of human complement and its breakdown products has been detected in human serum by high-voltage starch-gel electrophoresis. Six phenotypes were observed in a study of 113 randomly chosen Caucasians. Their inheritance is controlled by four codominant alleles at an autosomal locus. The gene frequencies in this study were C3(1), 0.21; C3(2), 0.77; C3(3), approximately 0.01; and C3(4), approximately 0.004.

Alleles↗
PubMed1968

Fetal hemoglobin variants in mice.

Two strains of mice, DBA and C3H, have a fetal globin polypeptide chain which differs in electrophoretic mobility from the corresponding fetal chain of the C57B1 strain. Mice of the DBA and C3H strains also differ from those of the C57B1 in adult hemoglobin type. Results of backcrossing the (DBA x C57B1) hybrid to the C57B1 suggest that the fetal chain locus and the adult beta-chain locus are closely linked.

Alleles↗
PubMed1967

Antibody variability. Somatic recombination between the elements of "antibody gene pairs" may explain antibody variability.

I have analyzed the available amino acid sequence data from 30 myelomatosis-derived proteins. Several types of variation are apparent. I conclude that a major and genetically predetermined contribution to the variability of these proteins and of antibodies could be provided by chromosomal rearrangements resulting from somatic recombination between similar but not identical genes in antibody gene pairs. My hypothesis suggests many new types of experiment and can be tested (31).

Amino Acid Sequence↗
PubMed1965

Disulfide-bond cleavage and formation in proteins.

Disulfide bonds can be cleaved at an alkaline pH by treating a protein with excess of a reagent disulfide in the presence of catalytic amounts of thiol. The cleavage products are stable and can be isolated; they contain the mixed disulfide between the reagent and the exposed thiol groups of the protein. The extent of cleavage is readily controlled by the pH of the reaction, temperature, and the addition of urea. Disulfide bonds cleaved by the reaction can be re-formed by exposing the mixed disulfide of the protein to catalytic amounts of thiol. Specific side chains can be added on to the thiol groups in native proteins by treatment with a reagent disulfide alone.

Buffers↗
PubMedDate not supplied

Duplication within the haptoglobin Hp2 gene.

DNA sequencing shows that the intragenic duplication within the human haptoglobin Hp2 allele was formed by a non-homologous, probably random, crossing-over within different introns of two Hp1 genes, probably in an Hp1F / Hp1S heterozygote.

Alleles↗
PubMedDate not supplied

Insertion of DNA sequences into the human chromosomal beta-globin locus by homologous recombination.

A 'rescuable' plasmid containing globin gene sequences allowing recombination with homologous chromosomal sequences has enabled us to produce, score and clone mammalian cells with the plasmid integrated into the human beta-globin locus. The planned modification was achieved in about one per thousand transformed cells whether or not the target gene was expressed.

Base Sequence↗
PubMedDate not supplied

Targetted correction of a mutant HPRT gene in mouse embryonic stem cells.

Two recent developments suggest a route to predetermined alterations in mammalian germlines. These are, first, the characterization of mouse embryonic stem (ES) cells that can still enter the germline after genetic manipulation in culture and second, the demonstration that homologous recombination between a native target chromosomal gene and exogenous DAN can be used in culture to modify specifically the target locus. We here use gene targetting functionally to correct the mutant hypoxanthine-guanine phosphoribosyl transferase (HPRT) gene in the ES cell line which has previously been isolated and used to produce an HPRT-deficient mouse. This modification of a chosen gene in pluripotent ES cells demonstrates the feasibility of this route to manipulating mammalian genomes in predetermined ways.

Animals↗