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Biomedical subjects

G F Saunders

Publications and source records attributed to G F Saunders.

At least 145 records · Page 8Linked to original sources
PubMed1976

Preparation of pancreatic mRNA: cell-free translation of an insulin-immunoreactive polypeptide.

Total nucleic acid extraction and selection of poly A-containing molecules yield preparative quantities of undegraded mRNA from adult and fetal pancreas. Using a stringent immunoassay, this mRNA is found to direct the synthesis of an immunoreactive insulin polypeptide in the wheat germ translation system. On sodium dodecyl sulfate polyacrylamide gels, this polypeptide (12,000-13,000 daltons) is larger than proinsulin (9,000 daltons).

Aging↗
PubMed1975

Localization of cytoplasmic-membrane-associated DNA in human chromosomes.

In situ hybridization was used to localize the sites of the repeated sequences of cytoplasmic-membrane-associated DNA (cmDNA) in human chromosomes. cmDNA was mainly present in the heterochromatic regions of chromosomes 9. Although cmDNA has buoyant densities in neutral and alkaline CsCl gradients similar to those of human satellite C DNA, which also is localized in the heterochromatic region of chromosomes 9, cmDNA was not homologous to satellite C DNA as determined by DNA-complementary RNA hybridization. These results are in agreement with our previous studies, which indicated that cmDNA is a unique species of human DNA.

Binding Sites↗
PubMed1975

Genome complexity and in vivo transcription in human leukemic leukocytes.

Human DNA contains 35 percent repetitive and 65 percent nonrepetitive sequences. Eight satellite DNAs have now been identified in human DNA. The highly repetitive non-satellite sequences are arranged in blocks 1,100 nucleotides long and interspersed with intermediate repetitive and nonrepetitive sequences greater than 2,500 nucleotides long. Approximately 2.5-3.9 percent of the nonrepetitive sequences are represented in total cellular RNA of normal and leukemic leukocytes.

Base Sequence↗
PubMed1973

125 I-labeled DNA-RNA hybrids in cytological preparations.

RNA complementary to bulk humanplacental DNA was synthesized in vitro both in the presence and absence of (3)H-labeled ribonucleotides. The (3)H-labeled RNA was used directly for hybridization to the DNA of human metaphase chromosomes, whereas the unlabeled complementary RNA was labeled chemically with (125)I before hybridization. A comparison of autoradiographs produced by either isotope revealed no qualitative differences in the chromosomal annealing sites of the same population of RNA molecules. Since (125)I-labeled nucleic acids give similar, if not identical, results as do (3)H-labeled nucleic acids in in situ hybridization experiments, their use should make possible the localization of genetic elements for which tritium labeling methods are either inadequate or not possible.

Autoradiography↗
PubMed1973

Action of rifamycin derivatives on RNA polymerase of human leukemic lymphocytes.

The mechanism of inhibition of human RNA polymerase by four rifamycin derivatives was investigated. Derivative AF/013 (3-formyl rifamycin SV:O-n-octyloxime) with strong hydrophobic side chains prevents the polymerase from binding to DNA and also affects the size of RNA synthesized. Derivative PR/19 (3'-acetyl-1'-benzyl-2'-methylpyrrolo[3,2-c]-4-desoxy-rifamycin SV) only affects RNA synthesis when RNA polymerase has been previously incubated with the drug or when the reaction was performed at high salt concentration [0.14 M (NH(4))(2)-SO(4)]. Our results suggest that these drugs exert their inhibitory actions by binding to the enzyme instead of DNA.

DNA-Directed RNA Polymerases↗