Gilbert D M, Cohen S N
Cell. 1987 Jul 3;50(1):59-68. doi: 10.1016/0092-8674(87)90662-3.
Bovine papilloma virus (BPV) replicates as a multicopy nuclear plasmid in mouse fibroblasts. Using fluorescence activated cell sorting and mitotic selection procedures, we show that the replication of BPV occurs throughout S phase of the cell cycle and that replication is confined to S phase. After one round of chromosomal DNA replication, almost one quarter of BPV plasmids have replicated more than once, while a similar number of plasmids have not replicated at all. While multiple forms of BPV exist in the cell, all forms show the same pattern of replication. These results are consistent with a model in which BPV plasmids are chosen at random for replication throughout, and only during, S phase and support the view that the completion of S phase is a specifically activated event in the cell cycle rather than simply the end of one round of chromosomal DNA replication.
牛乳头瘤病毒（BPV）在小鼠成纤维细胞中作为多拷贝核质粒进行复制。利用荧光激活细胞分选和有丝分裂选择程序，我们发现BPV的复制发生在细胞周期的整个S期，且复制局限于S期。一轮染色体DNA复制后，近四分之一的BPV质粒复制了不止一次，而同样数量的质粒根本没有复制。虽然细胞中存在多种形式的BPV，但所有形式都表现出相同的复制模式。这些结果与一个模型一致，即BPV质粒在整个S期随机被选择进行复制，且仅在S期复制，支持了S期的完成是细胞周期中一个特定激活事件的观点，而不仅仅是一轮染色体DNA复制的结束。
