Koury M J, Bondurant M C
Division of Hematology, Vanderbilt Center, Nashville, Tennessee 37232.
J Cell Physiol. 1988 Oct;137(1):65-74. doi: 10.1002/jcp.1041370108.
Erythroblasts isolated from the spleens of mice infected with the anemia-inducing strain of Friend virus (FVA cells)-are erythropoietin (EP)-sensitive cells at the late colony forming unit-erythroid (CFU-E) and cluster forming unit stages of differentiation (Koury et al., J. Cell. Physiol. 121:526-532, 1984). We investigate here the EP requirements of FVA cells in vitro for viability, proliferation, and maturation. By delaying the addition of EP to FVA cell cultures or by withdrawing EP at early times of culture, the subsequent viability, cell numbers, and maturation were diminished. The longer the delay in EP addition or the earlier the EP withdrawal, the more diminished these parameters were when compared to cultures which contained EP throughout the 48 h of differentiation. FVA cells had a period of EP requirement in vitro that lasted for only 24 h or less after the initiation of culture. During these crucial first 24 h, EP induced an increase in the synthesis of all size classes of RNA. Protein synthesis was maintained at a stable level in cells cultured with EP, but it declined in cells cultured without it. In contrast, the synthesis rate of DNA and the content of DNA per cell were not affected by the presence of EP in the culture. However, FVA cells cultured without EP had progressive accumulation of small sized DNA due to breakage of higher molecular weight DNA. The rate of DNA breakdown was sufficient to prevent DNA accumulation and thus it probably plays a role in the abortion of cell proliferation. No such breakage was found in cells cultured with EP. Our results indicate that EP exerts an effect on FVA cells in culture which is reflected in their viability, cell number, and maturation. This effect is not mediated by a stimulation of the rate of DNA synthesis, but is accompanied by stimulation of overall RNA synthesis and maintenance of protein synthesis.
从感染了致贫血性弗氏病毒株（FVA细胞）的小鼠脾脏中分离出的成红细胞，在红细胞集落形成单位（CFU-E）后期和分化的集簇形成单位阶段是对促红细胞生成素（EP）敏感的细胞（库里等人，《细胞生理学杂志》121:526 - 532，1984年）。我们在此研究FVA细胞在体外对生存能力、增殖和成熟的EP需求。通过延迟向FVA细胞培养物中添加EP或在培养早期撤去EP，随后的生存能力、细胞数量和成熟度都会降低。与在整个48小时分化过程中都含有EP的培养物相比，添加EP的延迟时间越长或撤去EP的时间越早，这些参数降低得就越多。FVA细胞在体外有一段对EP的需求期，在培养开始后仅持续24小时或更短时间。在这关键的最初24小时内，EP诱导了所有大小类别的RNA合成增加。在用EP培养的细胞中蛋白质合成维持在稳定水平，但在没有EP培养的细胞中蛋白质合成下降。相比之下，DNA的合成速率和每个细胞的DNA含量不受培养物中EP存在的影响。然而，在没有EP培养的FVA细胞中，由于高分子量DNA的断裂，小尺寸DNA逐渐积累。DNA断裂的速率足以阻止DNA积累，因此它可能在细胞增殖的中止中起作用。在用EP培养的细胞中未发现这种断裂。我们的结果表明，EP对培养中的FVA细胞产生影响，这体现在它们的生存能力、细胞数量和成熟度上。这种影响不是由DNA合成速率的刺激介导的，而是伴随着整体RNA合成的刺激和蛋白质合成的维持。
