Roberts J M, Weintraub H
Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, Washington 98104.
Cell. 1988 Feb 12;52(3):397-404. doi: 10.1016/s0092-8674(88)80032-1.
We show that in stable monkey cell lines, the replication of a chimeric SV40-BPV episomal replicon occurs once and only once per cell cycle. The copy number of this episome is stably maintained even when an excess of the limiting initiation factor T antigen is provided. These experiments therefore uncover a cis-acting negative control mechanism whereby replication control is not focused on limiting the activity of positive factors; rather, replication is permitted in unreplicated replicons but is actively prevented, in cis, in replicons that have already been duplicated. We also find that the initiation factor SV40 T antigen remains associated with its SV-BPV episomal template in a kinetically stable and potentially heritable state.
我们发现，在稳定的猴细胞系中，嵌合型SV40 - BPV游离型复制子的复制在每个细胞周期中发生一次且仅发生一次。即使提供过量的限制性起始因子T抗原，这种游离型复制子的拷贝数仍能稳定维持。因此，这些实验揭示了一种顺式作用的负调控机制，即复制调控并非着重于限制正调控因子的活性；相反，未复制的复制子允许复制，但已复制的复制子会在顺式作用下被积极阻止复制。我们还发现，起始因子SV40 T抗原与其SV - BPV游离型模板保持着动力学稳定且可能可遗传的结合状态。
