The relationship between the activity of DNA-dependent RNA polymerase I and the rate of synthesis of rRNA in hepatoma cells in culture.
The relationship between the activity of DNA-dependent RNA polymerase I and the rate of synthesis of rRNA in hepatoma cells in culture.
复制标题
培养的肝癌细胞中 DNA 依赖性 RNA 聚合酶 I 的活性与 rRNA 合成速率之间的关系。
DOI：
10.1042/bj1940043
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
Wood,KM
中科院分区：
文献类型：
--
作者：
ThompsonJr,EA;KeithJr,RH;Cavanaugh,AH;Wood,KM
从可移植的小鼠肝癌H6和H129建立细胞培养系。两种细胞系在含有5%胎牛血清的培养基中培养时，倍增时间约为30 h。H6细胞含有比H129细胞多约3-4倍的DNA依赖性RNA聚合酶I（Pol I;核糖核苷三磷酸-RNA核苷酸转移酶，EC 2.7.7.6）。此外，H6细胞的酶比H129细胞的酶更不耐热。在两种细胞系中测定28 S rRNA的稳态含量。H6细胞的指数生长培养物含有约6.5pg的28 S rRNA/细胞，并且H129细胞的类似培养物含有约5.8pg/细胞。两种细胞系的静止培养物含有约2 pg的28 S rRNA/细胞。用两种不同的方法测定了H6和H129细胞28 SrRNA的半衰期为16- 17小时。已知周转率和稳态浓度，可以计算出H6和H129细胞都以约0.25 pg/h/细胞的速率合成28 S rRNA。模板结合的Pol I活性的量在从H6和H129细胞培养物分离的细胞核中是相似的。这些数据表明，尽管H6细胞含有比H129细胞多3-4倍的Pol I，但两种细胞系合成rRNA的速率大致相同。
Cell culture lines were established from the transplantable mouse hepatomas H6 and H129. Both cell lines had a doubling time about 30 h when maintained in medium containing 5% foetal bovine serum. H6 cells contained about 3-4 times more DNA-dependent RNA polymerase I (Pol I; ribonucleoside triphosphate–RNA nucleotidyltransferase, EC 2.7.7.6) than did H129 cells. Moreover, the H6-cell enzyme was more heat-labile than that from H129 cells. Steady-state contents of 28S rRNA were measured in both cell lines. Exponentially growing cultures of H6 cells contained about 6.5pg of 28S rRNA/cell, and similar cultures of H129 cells contained about 5.8pg/cell. Stationary cultures of both cell lines contained about 2pg of 28S rRNA/cell. By two different techniques, the half-time for turnover of 28S rRNA was estimated to be 16-17h for both H6 and H129 cells. Knowing the turnover rate and the steady-state concentration, one may calculate that both H6 and H129 cells synthesize 28S rRNA at a rate of about 0.25 pg/h per cell. The amount of template-bound Pol I activity was similar in nuclei isolated from H6 and H129 cell cultures. These data indicate that, although H6 cells contained 3-4 times more Pol I than did H129 cells, both cell lines synthesized rRNA at about the same rate.