Synchronized Chinese hamster cells

Highfield, D. P., and Dewey, W. C., 1972, Inhibition of DNA synthesis in synchronized Chinese hamster cells treated in G1 or early S phase with cycloheximide or puromy-cin, Exp. Cell Res. 75 314. 

Cell cycle studies of histone phosphorylation using synchronized Chinese hamster ovary cells and HeLa S-3 cells demonstrated that HI and H3 are phosphorylated at different times during the cell cycle, while H2A and H4 are phosphorylated at uniform rates throughout the cell cycle [4—6]. Kinetic studies of the phosphorylation of H2A and H4 in trout testis indicate that these histones are phosphorylated shortly after synthesis [7]. Phosphorylation of H4 did not occur appreciably until after a series of acetylation and deacetylation events, while H2A was phosphorylated shortly after synthesis followed by dephosphorylation. 

Although the precise mechanism of action of paclitaxel in enhancing radiation effects is not clear, one of the proposed mechanisms is its effect on the cell cycle. Its effects on the microtubules result in an M-phase arrest (55). Experiments done on synchronously dividing Chinese hamster cells have shown that cells in M and G2 are most sensitive to the effects of radiation (56). 

Goth-Goldstein, R. and Burki, H.J. (1980). Ethylnitrosourea-induced mutagenesis in asynchronous and synchronous Chinese hamster ovary cells, Mutat. Res. 69,127. 

Studies of synchronized V79 Chinese hamster cells treated in G1 with cisplatin showed that depression of DNA synthesis in these cells was the result of a decrease in DNA synthetic rate, rather than a decreased rate of entry of cells into S (62). 

Chapman, J. D., Webb, R. G., and Borsa, J. (1971). ATP pool levels in synchronously growing Chinese hamster cells. J. Cell Biol. 49, 229-233. 

In HeLa ceils hydroxyurea is an efficient inhibitor of histone synthesis. This action requires protein synthesis and leads to rapid disappearance of cytoplasmatic histone mRNA The effect is not specific for hydroxyurea since suppression of DNA synthesis by arabino-cytosine or temperature-sensitive mutations yields analogous results. Similarly, the synthesis of some enzymes necessary for DNA replication and active in S-phase is altered by hydroxyurea. Increased activity of ribonucleotide reductase in HeLa and in hamster cells and of the salvage enzyme thymidine kinase in HeLa cells and KB cells has been observed, probably as a consequence of the increased fraction of cells in S-phase. Repression occurs for thymidine kinase in human lymphocytes and for ornithine decarboxylase in Chinese hamster fibroblasts whereas no or only slight effects were seen on ribonucleotide reductase in hamster fibroblasts , on thymidylate synthase in extracts from synchronous mouse cells " , and on DNA polymerase in rabbit kidney cells or HeLa cells . ... 

Choice of cells for synchronization is largely up to the investigator. However, the use of the shake-off technique (Tobey et al, 1967) described here requires cells that remain firmly attached to the substrate during interphase but with relatively loosely attached metaphase cells. Chinese hamster ovary cells have been found to fit this bill perfectly. 

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