Allaudeen H S, Rani G
Nucleic Acids Res. 1982 Apr 10;10(7):2453-65. doi: 10.1093/nar/10.7.2453.
We have determined the levels of cellular DNA polymerases and Epstein-Barr virus specific DNA polymerase in three Burkitt's lymphoma cell lines producing varying amounts of EBV, one of which was induced by 12-0-tetra-decanoylphorbol-13-acetate (TPA). There was a proportional increase in the level of EBV-DNA polymerase with an increase in the percent of virus-producing cells. However, there was a reciprocal relationship between the levels of EBV-DNA polymerase and DNA polymerase alpha i.e., in cell line containing the highest level of EBV-DNA polymerase, activity of DNA polymerase alpha, but not of DNA polymerase beta, was reduced to an insignificantly low level. TPA does not have any direct effect on activities of either EBV-DNA polymerase or DNA polymerase alpha. EBV-DNA polymerases isolated from cells grown with or without TPA are indistinguishable in their properties such as elution position on phosphocellulose column, molecular weight, mono and divalent cation requirements, pH optimum, and other requirements for optimum activity. Addition of crude extracts of cells grown in presence of TPA to the purified DNA polymerase alpha did not inhibit its activity indicating that the observed loss was not due to any specific inhibitor present in TPA treated cells. Raji, a nonproducer cell line, did not contain EBV-DNA polymerase. There was no induction of EBV-DNA polymerase when Raji cells were grown in presence of TPA. The phenomenon of reduction in the levels of DNA polymerase alpha in cells induced to produce EBV may represent a mechanism by which the host DNA replication is shut off following virus infection.
我们测定了三种产生不同量EB病毒（Epstein-Barr virus，EBV）的伯基特淋巴瘤细胞系中的细胞DNA聚合酶和EBV特异性DNA聚合酶水平，其中一种细胞系是由12-0-十四烷酰佛波醇-13-乙酸酯（TPA）诱导产生的。随着产生病毒的细胞百分比增加，EBV-DNA聚合酶水平呈比例增加。然而，EBV-DNA聚合酶水平与DNA聚合酶α之间存在反比关系，即，在含有最高水平EBV-DNA聚合酶的细胞系中，DNA聚合酶α的活性（而非DNA聚合酶β的活性）降低到极低水平。TPA对EBV-DNA聚合酶或DNA聚合酶α的活性均无直接影响。从添加或未添加TPA培养的细胞中分离出的EBV-DNA聚合酶，在诸如磷酸纤维素柱上的洗脱位置、分子量、单价和二价阳离子需求、最适pH以及其他最佳活性需求等特性方面并无差异。将在TPA存在下培养的细胞粗提物添加到纯化的DNA聚合酶α中，并未抑制其活性，这表明观察到的活性降低并非由于TPA处理的细胞中存在任何特异性抑制剂。Raji，一种不产生病毒的细胞系，不含EBV-DNA聚合酶。当Raji细胞在TPA存在下培养时，未诱导出EBV-DNA聚合酶。在被诱导产生EBV的细胞中DNA聚合酶α水平降低的现象，可能代表了一种机制，通过该机制宿主DNA复制在病毒感染后被关闭。
