Umekawa H, Kondoh K, Furuichi Y, Takahashi T, Yoshida S
Department of Agricultural Chemistry, Faculty of Bioresources, Mie University, Japan.
Biochem Int. 1992 Dec;28(6):1063-70.
We measured the levels of the DNA polymerases alpha, beta, and gamma in human peripheral lymphocyte cells stimulated with Tora-mame lectin (TM-lectin) and the induction patterns were compared to those with other plant lectins, i.e., phytohemagglutinin (PHA) and pokeweed mitogen (PWM). The maximum activity of DNA polymerase alpha in lymphocytes was achieved at the concentration of 10 micrograms/ml with TM lectin and the dose response curve of TM lectin showed a sharp peak in contrast to that of PWM. During prolonged stimulation for 10 days, the time course of DNA polymerase alpha induction was different among these three lectins. A peak of alpha-enzyme was correlated with maximal incorporation of [3H]thymidine and was observed on the fourth day with TM lectin, on the third day with PHA, and sixth day with PWM. DNA polymerase beta in lymphocytes was also activated by the addition of these proteins. Two different peaks were observed during a 10-day period with every lectin, and TM lectin was most potent stimulator among them. The activity of DNA polymerase gamma in lymphocytes was at a very low but detectable level which increased slightly in response to TM lectin treatment. Although some variability of gamma-enzyme activity was observed after the seventh day, the pattern in the course of 7 days was similar among the lectins.
我们测定了用豆凝集素（TM凝集素）刺激的人外周淋巴细胞中DNA聚合酶α、β和γ的水平，并将诱导模式与其他植物凝集素，即植物血凝素（PHA）和商陆有丝分裂原（PWM）的诱导模式进行了比较。淋巴细胞中DNA聚合酶α的最大活性在TM凝集素浓度为10微克/毫升时达到，与PWM相比，TM凝集素的剂量反应曲线显示出一个尖锐的峰值。在长达10天的延长刺激过程中，这三种凝集素诱导DNA聚合酶α的时间进程有所不同。α酶的峰值与[3H]胸腺嘧啶核苷的最大掺入相关，用TM凝集素时在第4天观察到，用PHA时在第3天观察到，用PWM时在第6天观察到。淋巴细胞中的DNA聚合酶β也通过添加这些蛋白质而被激活。在10天的时间里，每种凝集素都观察到两个不同的峰值，其中TM凝集素是最有效的刺激剂。淋巴细胞中DNA聚合酶γ的活性处于非常低但可检测的水平，对TM凝集素处理有轻微增加。虽然在第7天后观察到γ酶活性有一些变化，但在7天的过程中，凝集素之间的模式相似。
