scholarly journals NUCLEAR MEMBRANES OF CULTURED MAMMALIAN CELLS IN THE PERIOD PRECEDING DNA SYNTHESIS

1965 ◽  
Vol 25 (1) ◽  
pp. 103-107 ◽  
Author(s):  
Susumu Kishimoto ◽  
Irving Lieberman
Keyword(s):  
Ionizing Radiation ◽  
Dna Synthesis ◽  
Electrophoretic Mobility ◽  
Mammalian Cells ◽  
Elevated Level ◽  
Actinomycin D ◽  
Kidney Cells ◽  
Nuclear Membranes ◽  
L Cells

When kidney cells are cultured directly from the rabbit, the nuclear membranes undergo a change that can be measured as an increase in electrophoretic mobility. The change appears to begin immediately upon culture and is maximal 2 hours later, after which the mobility remains constant at the elevated level. Actinomycin D and p-fluorophenylalanine, but not EDTA or ionizing radiation, suppress the increase in nuclear electrophoretic mobility. With synchronously growing L cells, no change was detected in nuclei from cells taken during various parts of the division cycle.

Initiation of DNA synthesis in a system of synchronized L-cells: effect of actinomycin D

1968 ◽  
Vol 14 (1) ◽  
pp. 113-122 ◽  
Author(s):  
C. Mittermayer ◽  
P. Kaden ◽  
U. Trommershaeuser ◽  
W. Sandritter
Keyword(s):  
Dna Synthesis ◽  
Actinomycin D ◽  
L Cells

Effect of pulsing electromagnetic fields on DNA synthesis in mammalian cells in culture

1986 ◽  
Vol 42 (2) ◽  
pp. 185-186 ◽  
Author(s):  
K. Takahashi ◽  
I. Kaneko ◽  
M. Date ◽  
E. Fukada
Keyword(s):  
Dna Synthesis ◽  
Electromagnetic Fields ◽  
Mammalian Cells ◽  
Cells In Culture

scholarly journals Poly-L-ornithine-mediated transformation of mammalian cells.

1987 ◽  
Vol 7 (6) ◽  
pp. 2286-2293 ◽  
Author(s):  
V C Bond ◽  
B Wold
Keyword(s):  
Cell Lines ◽  
Mammalian Cells ◽  
High Efficiency ◽  
Protein Product ◽  
Marker Genes ◽  
Recipient Mouse ◽  
L Cells ◽  
Dna And Rna ◽  
Selectable Marker Genes

Poly-L-ornithine has been used to introduce DNA and RNA into mammalian cells in culture. Ornithine-mediated DNA transfer has several interesting and potentially useful properties. The procedure is technically straightforward and is easily applied to either small or large numbers of recipient cells. The efficiency of transformation is high. Under optimal conditions, 1 to 2% of recipient mouse L cells take up and continue to express selectable marker genes. DNA content of transformants can be varied reproducibly, yielding cells with just one or two copies of the new gene under one set of conditions, while under a different set of conditions 25 to 50 copies are acquired. Cotransformation and expression of physically unlinked genes occur at high efficiency under conditions favoring multiple-copy transfer. Polyornithine promotes gene transfer into cell lines other than L cells. These include Friend erythroleukemia cells and NIH 3T3 cells. Both are transformed about 1 order of magnitude more efficiently by this procedure than by standard calcium phosphate products. However, the method does not abolish the large transformation efficiency differences between these cell lines that have been observed previously by other techniques. (vi) mRNA synthesized in vitro was also introduced into cells by this method. The RNA was translated resulting in a transient accumulation of the protein product.

Inhibition of recovery from damage induced by ionizing radiation in mammalian cells

1988 ◽  
Vol 13 (4) ◽  
pp. 285-299 ◽  
Author(s):  
Lloyd R. Kelland ◽  
G.Gordon Steel
Keyword(s):  
Ionizing Radiation ◽  
Mammalian Cells

scholarly journals Primase p49 mRNA expression is serum stimulated but does not vary with the cell cycle.

1989 ◽  
Vol 9 (5) ◽  
pp. 1940-1945 ◽  
Author(s):  
B Y Tseng ◽  
C E Prussak ◽  
M T Almazan
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Small Subunit ◽  
Mrna Levels ◽  
Proliferating Cells ◽  
Restriction Point ◽  
Serum Stimulation ◽  
G1 Cells

Expression of the small-subunit p49 mRNA of primase, the enzyme that synthesizes oligoribonucleotides for initiation of DNA replication, was examined in mouse cells stimulated to proliferate by serum and in growing cells. The level of p49 mRNA increased approximately 10-fold after serum stimulation and preceded synthesis of DNA and histone H3 mRNA by several hours. Expression of p49 mRNA was not sensitive to inhibition by low concentrations of cycloheximide, which suggested that the increase in mRNA occurred before the restriction point control for cell cycle progression described for mammalian cells and was not under its control. p49 mRNA levels were not coupled to DNA synthesis, as observed for the replication-dependent histone genes, since hydroxyurea or aphidicolin had no effect on p49 mRNA levels when added before or during S phase. These inhibitors did have an effect, however, on the stability of p49 mRNA and increased the half-life from 3.5 h to about 20 h, which suggested an interdependence of p49 mRNA degradation and DNA synthesis. When growing cells were examined after separation by centrifugal elutriation, little difference was detected for p49 mRNA levels in different phases of the cell cycle. This was also observed when elutriated G1 cells were allowed to continue growth and then were blocked in M phase with colcemid. Only a small decrease in p49 mRNA occurred, whereas H3 mRNA rapidly decreased, when cells entered G2/M. These results indicate that the level of primase p49 mRNA is not cell cycle regulated but is present constitutively in proliferating cells.

A rapid method for preparation of nuclear membranes from mammalian cells

1976 ◽  
Vol 75 (1) ◽  
pp. 290-300 ◽  
Author(s):  
C.E. Hildebrand ◽  
R.T. Okinaka
Keyword(s):  
Rapid Method ◽  
Mammalian Cells ◽  
Nuclear Membranes
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