Pohjanpelto P, Nordling S, Knuutila S
Department of Virology, University of Helsinki, Finland.
Cytometry. 1994 Aug 1;16(4):331-8. doi: 10.1002/cyto.990160407.
Polyamines are found in all cells but their function is not fully understood. We have studied the effect of polyamines on the passage of cells through the cell cycle using a polyamine auxotrophic mutant, CHO-P22, which has no detectable ornithine decarboxylase activity. The ability of these cells to grow without serum allows efficient polyamine depletion. A flow cytometric analysis of DNA content and bromodeoxyuridine labeling showed that without added polyamines the cells accumulated in S-phase, the rate of DNA synthesis was retarded, and the entry into mitosis was blocked. Addition of polyamines to cultures deprived of polyamines induced cells in all phases of the cell cycle to reinitiate cycling. Earlier studies have shown that cells with damaged DNA are blocked from entering into mitosis but caffeine can partly overcome this block and induce premature chromosome condensation. Polyamine-depleted CHO-P22 cells responded to caffeine in the same way as cells with damaged DNA. These results show that polyamine depletion in CHO-P22 cells primarily affects DNA synthesis. The finding that polyamine-starved cells continuously take up bromodeoxyuridine without a corresponding increase in the amount of DNA is compatible with extensive repair of erroneous and/or damaged DNA. Polyamine auxotrophic Chinese hamster ovary (CHO) cells might be useful in studies on the regulation of mitosis in mammalian cells.
多胺存在于所有细胞中，但其功能尚未完全明确。我们利用一种多胺营养缺陷型突变体CHO-P22（该突变体无可检测到的鸟氨酸脱羧酶活性）研究了多胺对细胞通过细胞周期的影响。这些细胞在无血清条件下生长的能力使得多胺能够有效耗竭。对DNA含量和溴脱氧尿苷标记进行的流式细胞术分析表明，在不添加多胺的情况下，细胞在S期积累，DNA合成速率减慢，且进入有丝分裂受阻。向缺乏多胺的培养物中添加多胺可诱导细胞周期各阶段的细胞重新开始循环。早期研究表明，DNA受损的细胞会被阻止进入有丝分裂，但咖啡因可部分克服这一阻滞并诱导染色体提前凝聚。多胺耗竭的CHO-P22细胞对咖啡因的反应与DNA受损的细胞相同。这些结果表明，CHO-P22细胞中的多胺耗竭主要影响DNA合成。多胺饥饿的细胞持续摄取溴脱氧尿苷但DNA量却没有相应增加，这一发现与对错误和/或受损DNA的广泛修复相一致。多胺营养缺陷型中国仓鼠卵巢（CHO）细胞可能在哺乳动物细胞有丝分裂调控研究中有用。
