Futcher A B, Cox B S
J Bacteriol. 1984 Jan;157(1):283-90. doi: 10.1128/jb.157.1.283-290.1984.
The copy number and stability of artificial 2-micron circle-based plasmids have been accurately measured in [Cir+] and [Cir0] strains of Saccharomyces cerevisiae. We conclude that (i) instability and copy number vary greatly from plasmid to plasmid; (ii) instability and copy number are negatively correlated--that is, high copy number is associated with low instability; (iii) it is difficult to reconcile this variability with a strict and direct system of copy number control; (iv) instabilities are much higher than expected from random partition and the observed copy numbers: this may imply partition which is less efficient than random. Even so, (v) the partitioning of 2-micron circle-like plasmids is more efficient than that of ARS-based plasmids, which hints at the existence of a system for the (inefficient) distribution of 2-micron circles.
已在酿酒酵母的[Cir+]和[Cir0]菌株中准确测量了基于人工2微米环状质粒的拷贝数和稳定性。我们得出以下结论:(i)不同质粒的不稳定性和拷贝数差异很大;(ii)不稳定性和拷贝数呈负相关——也就是说,高拷贝数与低不稳定性相关;(iii)难以将这种变异性与严格且直接的拷贝数控制系统相协调;(iv)不稳定性远高于随机分配和观察到的拷贝数所预期的水平:这可能意味着分配效率低于随机分配。即便如此,(v)2微米环状样质粒的分配比基于自主复制序列(ARS)的质粒更有效,这暗示存在一个用于(低效)分配2微米环的系统。