REGULATION OF FIBROBLAST CELL-CYCLE BY SERUM
REGULATION OF FIBROBLAST CELL-CYCLE BY SERUM
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DOI：
10.1038/260248a0
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发表时间：
1976-01-01
期刊：
影响因子：
64.8
通讯作者：
BROOKS, RF
中科院分区：
文献类型：
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作者：
BROOKS, RF
当“正常”成纤维细胞缺乏血清时，它们会停止生长并在细胞周期的 G1 或 G0 阶段积累。血清恢复后，细胞在经过明确的滞后期后开始准同步进入 S 期，这似乎是细胞类型的特征。根据 Todaroet al.2、Bürk3 和 Temin4 的研究，人们普遍认为，仅在该滞后期的一部分时间内暴露于血清就足以使细胞不可逆地启动一轮 DNA 复制。因此，仅在几个小时后和滞后期结束之前去除血清不会影响很大一部分人群随后的 DNA 合成。然而，很明显，这种“承诺”细胞的比例取决于血清脉冲的持续时间2-5。事实上，血清暴露时间和定型细胞比例之间的关系与时间近似呈线性关系，并且（对于 3T3 细胞）延伸到滞后期本身结束之后（图 1）。显然，一些在连续暴露于血清期间受到刺激而启动DNA合成的细胞在滞后期结束时并未定型，因为此时去除血清使标记细胞的比例在24小时时从76%降低到53%（图1b）。
WHEN “normal” fibroblasts are deprived of serum they cease growing and accumulate in the G1or G0stage of the cell cycle1. On restoration of serum, the cells begin to enter S phase quasi-synchronously after a well defined lag period which seems to be characteristic of the cell type. Following the studies of Todaroet al.2, Bürk3, and Temin4, it is widely believed that exposure to serum for only a portion of this lag period is sufficient to commit the cells irreversibly to initiate a round of DNA replication. Thus, removal of the serum after only a few hours, and before the end of the lag period, does not affect subsequent DNA synthesis in a significant proportion of the population. It has been apparent, nevertheless, that the proportion of such “committed” cells depends on the duration of the serum pulse2–5. Indeed, the relationship between the length of exposure to serum and the proportion of committed cells is approximately linear with time and (with 3T3 cells) extends beyond the end of the lag phase itself (Fig. 1). Clearly, some cells which are stimulated to initiate DNA synthesis during continuous exposure to serum are not committed by the end of the lag period, since removal of the serum at this point reduced the proportion of labelled cells, at 24 h, from 76 to 53% (Fig. 1b).