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Biomedical subjects

D Gillespie

Publications and source records attributed to D Gillespie.

At least 55 records · Page 3Linked to original sources
PubMed1985

Recent amplification of an alpha satellite DNA in humans.

A repeat sequence 682 base pairs (bp) long produced by cleavage of human DNA with Xba I restriction enzyme is composed of four tandemly arranged subunits with lengths of 171, 170, 171, and 170 bp each. The sequence organization of the 682 bp Xba I repeat bears a striking resemblance to other complex satellite DNAs of primates, including the Eco RI human alpha satellite family which also occurs as a 170 bp repeat. The Eco RI tetramer and the 682 bp Xba I repeat show a sequence divergence of 21%. The 682 bp Xba I repeat sequence is restricted to humans and is only distantly related to the previously reported 340 bp Xba human repeated DNA sequence. These finding are consistent with the concept of occasional amplifications of members or groups of members of alpha satellite DNA during human evolution. Amplifications apparently occurred after humans, apes and gibbons diverged from Old World monkeys (Eco RI satellite), after humans and apes diverged from gibbons (340 bp Xba I satellite) and after humans diverged from the great apes (682 bp Xba I satellite).

Animals↗
PubMed1984

Phosphoproteins altered by antiproliferative doses of human interferon- beta in a human bladder carcinoma cell line.

Phosphoproteins of control and IFN-beta treated human bladder carcinoma cells (RT4) were labelled in vitro with [32P]-ATP and analyzed by polyacrylamide gel electrophoresis. Cells treated with antiproliferative doses of IFN had reduced levels of phosphorylated 60 Kd and 40 Kd proteins. IFN also induced within 24 hours the modification of a low molecular weight phosphoprotein doublet in the 22-24,000 molecular weight range. The ability to phosphorylate high molecular weight proteins by the in vitro procedures was generally depressed by IFN treatment. There was a dramatic shift in the phosphorylation of alkali stable phosphoamino acids associated with proteins in the 43-50,000 molecular weight range in IFN-treated cells. Preliminary studies indicate that at least some of the IFN-induced modifications of cellular phosphoproteins may result from transcriptional control of specific oncogenes.

Adenosine Triphosphate↗
PubMed1983

Quantitative binding of covalently closed circular DNA to nitrocellulose in NaI.

A procedure for quantitatively binding covalently closed circular DNA to nitrocellulose is detailed. The procedure involves making DNA saturated with respect to Nat at 25 degrees C, denaturing the DNA by heating to 80-100 degrees C, then passing the DNA-NaI solution through a nitrocellulose membrane at 50-60 degrees C. Form I DNA remains denatured throughout the loading procedure and is quantitatively deposited on the membrane as denatured DNA. The mechanism of binding DNA to nitrocellulose in NaI appears to be different from the binding promoted by NaCl.

Collodion↗
PubMed1983

Three organizations of human DNA.

Human DNA was denatured, annealed to low C0t, and fractionated by centrifugation to equilibrium on gradients of NaI. Three well-defined zones resulted. The topmost, least dense zone contained satellite DNA. The bottom zone contained molecules bearing infrequent sequences and short repeated DNA. The middle zone contained molecules bearing infrequent sequences, short repeated DNA, and long repeated DNA. The NaI pattern was independent of single-strand DNA chain length from 5 to 30 kilobases. Structural genes were found in the organization bearing long repeats.

Base Sequence↗
PubMed1983

Biological activity of mRNA immobilized on nitrocellulose in NaI.

In 12.2 molal NaI and at 25 degrees C or below, mRNA bound to nitrocellulose while DNA and rRNA did not. Neither the poly(A) tract nor the cap were required for binding. The immobilized RNA could be translated, reverse transcribed, hybridized with radioactive probes, or released for further manipulation. mRNA was efficiently transferred from polyacrylamide to nitrocellulose in NaI. Baking was not required to fix NaI-immobilized mRNA to nitrocellulose. When cells dissolved in 12.2 molal NaI were filtered through nitrocellulose, mRNA became selectively bound (quickblot). The quick-blot system utilizing protease and detergents to prepare cells for NaI solubilization was especially suitable in quantitative, rapid screening of cells for expression of specific genes. Expression of highly repeated DNA sequences was detected in human leukemia cells.

Collodion↗
PubMed1983

Quick-blot: selective mRNA or DNA immobilization from whole cells.

Quick-blot, a method for selectively immobilizing either mRNA or DNA on nitrocellulose, is described in detail. Essential elements of the procedure for immobilizing DNA include tissue lysis, proteinase K treatment, solubilization of nucleic acids in hot 12.2 molal NaI, passage through a nitrocellulose filter, and acetylation of residual protein with acetic anhydride. Advantages include speed, quantitative recovery, low background, and elimination of the usual baking step. Essential elements of the procedure for selectively immobilizing mRNA include dissolving cells in Brij-35 and desoxycholate, proteinase K treatment, solubilizing nucleic acids in room temperature 12.2 molal NaI, filtration through nitrocellulose, and acetylation of residual protein. Advantages include selective immobilization of mRNA but not tRNA, rRNA, or DNA, and the maintenance of biological activity of the immobilized mRNA. Control experiments to optimize the procedures and examples of their application are shown.

Cells↗
PubMed1983

Concerted evolution of human interferon alpha genes.

Multiple interferon (IFN) alpha genes characterize divergent animal species, yet human interferon alpha (HuIFN-alpha) genes are closely related in nucleotide sequence. Either the IFN-alpha genes derived from common ancestor sequences after divergence of these animals, or the HuIFN-alpha genes that have been studied underwent concerted evolution. Evidence suggesting that concerted evolution did occur to some unknown extent raises doubts about the important conclusion of recent divergence of the HuIFN-alpha gene family.

Animals↗
PubMed1982

New orientations of ancestral, "long interspersed repeated sequences" (LINES) in human DNA.

Three sets of long, interspersed repeated sequences (LINES) are described in human DNA. Each set contains two cleavage sites for the restriction endonuclease, XbaI. One set, called the Xba 850 LINES was detected only in gibbons, apes and man but is related in sequence to a more ancestral LINES family, the Kpn 1200 LINES, and in fact some Xba 850 LINES members retained the ancestral spacing of KpnI cleavage sites. The facts that the Xba 850 LINES appear as a subset of the Kpn 1200 LINES and vice versa and that the Xba 850 LINES are restricted to a smaller phylogenetic group than the Kpn 1200 LINES prompted the speculation that the Xba 850 LINES originated by a relatively recent amplification of one or a few Kpn 1200 LINES sequences.

Animals↗