Cell cycle parameters of Chinese hamster ovary cells during exponential, polyamine-limited growth.
We have previously shown that Chinese hamster ovary cells made polyamine deficient by treatment with alpha-methylornithine, an inhibitor of ornithine decarboxylase, grow exponentially in culture at low densities at one-half the rate observed in untreated (control) cultures. In this study, the cell cycle of polyamine-limited cells was examined by using thymidine autoradiography, mitotic index analysis, and fraction labeled mitoses analysis. We found that the longer doubling time of inhibitor-treated cultures was a consequence of increases in the lengths of the G1 and S phases. The expansion of the S phase was proportional to the increase in doubling time (twofold), whereas the G1 phase was lengthened by slightly more than a factor of 2. The lengths of the G2 and M phases were essentially unchanged. Putrescine stimulated the growth of inhibitor-treated cultures and restored the cell cycle parameters to those of untreated cells.
Harada
J J
JJ
Department of Biochemistry, University of Washington, Seattle 98195, USA.
Morris
D R
DR
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D016466:CHO Cells; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D006224:Cricetinae; D005260:Female; D009952:Ornithine / Q000031:analogs & derivatives* / Q000494:pharmacology; D010053:Ovary / Q000166:cytology; D011073:Polyamines / Q000378:metabolism*; D011700:Putrescine / Q000378:metabolism
D000970:Antineoplastic Agents; D011073:Polyamines; C025025:alpha-methylornithine; D009952:Ornithine; D011700:Putrescine