Studies on temperature-sensitive mutants of Chinese hamster ovary cells affected in DNA synthesis

1980 ◽  
Vol 6 (5) ◽  
pp. 567-582 ◽  
Author(s):  
P. R. Srinivasan ◽  
Radhey S. Gupta ◽  
Louis Siminovitch
Keyword(s):  
Dna Synthesis ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Temperature Sensitive ◽  
Ovary Cells ◽  
Temperature Sensitive Mutants

Effects of ultraviolet light on synchronized Chinese hamster ovary cells; potentiation by hydroxyurea

1977 ◽  
Vol 28 (1) ◽  
pp. 29-48
Author(s):  
K. Burg ◽  
A.R. Collins ◽  
R.T. Johnson
Keyword(s):  
Dna Synthesis ◽  
Ultraviolet Light ◽  
Hela Cells ◽  
Chinese Hamster Ovary ◽  
Ultraviolet Irradiation ◽  
Chromosome Structure ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cells

We have examined the effects of hydroxyurea on u.v.-irradiated Chinese hamster CHO-KI cells. Ultraviolet irradiation followed by incubation with hydroxyurea causes only slight disruption of DNA and chromosome structure in CHO-KI cells compared with HeLa cells. There is, however, a clear potentiation by hydroxyurea of the u.v. killing of CHO-KI cells, which is most pronounced at those points in the cycle which are reported to have small DNA precursor pools. This potentiation is reduced when DNA precursors are provided together with hydroxyurea. These data are discussed in terms of an uncoupling of excision and repair DNA synthesis.

scholarly journals Continued initiation of DNA synthesis in arginine-deprived Chinese hamster ovary cells.

1977 ◽  
Vol 73 (1) ◽  
pp. 200-205 ◽  
Author(s):  
A S Weissfeld ◽  
H Rouse
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Cell Multiplication ◽  
Ovary Cells ◽  
Cell Cycle Phases

When exponentially growing CHO cells were deprived of arginine (Arg), cell multiplication ceased after 12 h, but initiation of DNA synthesis continued: after 48 h of starvation with continuous [3H]thymidine exposure, 85% of the population had incorporated label, as detected autoradiographically. Consideration of the distribution of exponential cells in the various cell cycle phases leads to a calculation that most cells in G1 at the time that Arg was removed, as well as those in S, engaged in some DNA synthesis during starvation. In contrast, isoleucine (Ile)-starved cells did not initiate DNA synthesis, as has been reported by others. Experiments with cells synchronized by mitotic selection confirmed this difference in Arg- and Ile- deprived behavior, but also showed that cells which underwent the mitosis leads to G1 transition during Arg starvation remained arrested in G1 (G0?). The results suggest that Arg-deprived cells continue to maintain some proliferative function(s) while Ile-deprived cells do not.

scholarly journals Isolation of Chinese hamster ovary cells that overproduce asparaginyl-tRNA synthetase.

1984 ◽  
Vol 4 (9) ◽  
pp. 1939-1941
Author(s):  
R E Cirullo ◽  
J J Wasmuth
Keyword(s):  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Trna Synthetase ◽  
Temperature Sensitive ◽  
Ovary Cells ◽  
Resistant Phenotype ◽  
Lines Of Evidence

Temperature-resistant revertants, derived from the temperature-sensitive CHO asparaginyl-tRNA synthetase mutant, Asn-5, were isolated and characterized. Several lines of evidence indicate that the temperature-resistant phenotype of the revertants is due to their overproducing the same altered enzyme present in the Asn-5 parent.

The Effects of X Rays on DNA Synthesis in Synchronized Chinese Hamster Ovary Cells

1980 ◽  
Vol 83 (1) ◽  
pp. 205 ◽  
Author(s):  
Tommie J. Laughlin ◽  
J. Herbert Taylor
Keyword(s):  
Dna Synthesis ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
X Rays ◽  
Ovary Cells

scholarly journals Centriole cycle in Chinese hamster ovary cells as determined by whole-mount electron microscopy.

1981 ◽  
Vol 91 (3) ◽  
pp. 814-821 ◽  
Author(s):  
R Kuriyama ◽  
G G Borisy
Keyword(s):  
Electron Microscopy ◽  
Dna Synthesis ◽  
Chinese Hamster Ovary ◽  
Structural Changes ◽  
Morphological Changes ◽  
Chinese Hamster Ovary Cells ◽  
Quantitative Description ◽  
Chinese Hamster ◽  
Ovary Cells ◽  
Whole Mount

In interphase Chinese hamster ovary (CHO) cells, the centrosome is attached to the nucleus very firmly. This nuclear-centrosome complex is isolated as a coherent structure by lysis and extraction of cells with Triton X-100 in a low ionic strength medium. Under these conditions, the ultrastructure of the centrioles attached to the nucleus can be discerned by electron microscopy of whole-mount preparations. The structural changes of the centrioles as a function of the cell cycle were monitored by this technique. Specifically, centriolar profiles were placed into six categories according to their orientation and the length ratio of daughter and parent centrioles. The proportion of centrioles in each category was plotted as a frequency histogram. The morphological changes in the centriole cycle were characterized by three distinguishable events: nucleation, elongation, and disorientation. The progress of centrioles through these stages was determined in synchronous populations of cells starting from S or M phase, in cells inhibited in DNA synthesis by addition of thymidine, and in cytoplasts. The results provide a quantitative description of the events of the centriole cycle. They also show that, in complete cells, nucleation, elongation, and disorientation are not dependent upon DNA synthesis. However, in cytoplasts, although elongation and disorientation occur as in normal cells, nucleation is blocked. Procentriole formation appeared to be inhibited by the removal of the nucleus. We suggest that coordination of centriole replication and nuclear replication may depend upon a signal arising from the nucleus.

Sign in / Sign up

Export Citation Format

Share Document