Holstein T W, David C N
Department of Zoology, University of Munich, Germany.
Dev Biol. 1990 Dec;142(2):392-400. doi: 10.1016/0012-1606(90)90360-u.
We have analyzed the cell cycle parameters of interstitial cells in Hydra oligactis. Three subpopulations of cells with short, medium, and long cell cycles were identified. Short-cycle cells are stem cells; medium-cycle cells are precursors to nematocyte differentiation; long-cycle cells are precursors to gamete differentiation. We have also determined the effect of different cell densities on the population doubling time, cell cycle length, and cell size of interstitial cells. Our results indicate that decreasing the interstitial cell density from 0.35 to 0.1 interstitial cells/epithelial cell (1) shortens the population doubling time from 4 to 1.8 days, (2) increases the [3H]thymidine labeling index from 0.5 to 0.75 and shifts the nuclear DNA distribution from G2 to S phase cells, and (3) decreases the length of G2 in stem cells from 6 to 3 hr. The shortened cell cycle is correlated with a significant decrease in the size of interstitial stem cells. Coincident with the shortened cell cycle and increased growth rate there is an increase in stem cell self-renewal and a decrease in stem cell differentiation.
我们分析了寡枝螅间质细胞的细胞周期参数。鉴定出了具有短、中、长细胞周期的三个细胞亚群。短周期细胞是干细胞；中周期细胞是刺细胞分化的前体细胞；长周期细胞是配子分化的前体细胞。我们还确定了不同细胞密度对间质细胞群体倍增时间、细胞周期长度和细胞大小的影响。我们的结果表明，将间质细胞密度从0.35个间质细胞/上皮细胞降低到0.1个间质细胞/上皮细胞，（1）将群体倍增时间从4天缩短到1.8天，（2）将[³H]胸腺嘧啶核苷标记指数从0.5提高到0.75，并使核DNA分布从G2期细胞转变为S期细胞，以及（3）将干细胞中G2期的长度从6小时缩短到3小时。缩短的细胞周期与间质干细胞大小的显著减小相关。与缩短的细胞周期和增加的生长速率同时出现的是干细胞自我更新增加和干细胞分化减少。
