COPY NUMBER AMPLIFICATION OF THE 2-MU-M CIRCLE PLASMID OF SACCHAROMYCES-CEREVISIAE
COPY NUMBER AMPLIFICATION OF THE 2-MU-M CIRCLE PLASMID OF SACCHAROMYCES-CEREVISIAE
复制标题
DOI：
10.1016/s0022-5193(86)80074-1
复制
发表时间：
1986-03-21
影响因子：
2
通讯作者：
FUTCHER, AB
中科院分区：
文献类型：
--
作者：
FUTCHER, AB
2 μ m的环是小的双链DNA质粒，其以约60个拷贝/细胞存在于几乎所有酿酒酵母菌株的细胞核中。该质粒对宿主细胞没有明显的表型效应，并且是许多用于酵母转化的有用载体的基础。在某些情况下，质粒显然能够在每个细胞周期复制一次以上;这种过度复制允许质粒维持在高拷贝数。该质粒具有两个反向重复序列，并编码催化这两个重复序列之间分子内重组的产物。模型提出重组导致拷贝数扩增。特别是，有人提出，在复制过程中的分子内重组翻转一个复制叉相对于其他的方向，使两个叉旅行在同一方向上围绕一个圆形的单体模板，产生一个大的多聚体从一个单体和一个单一的复制启动。
The 2 .mu.m circle is a small double stranded DNA plasmid that occurs at about 60 copies per cell in the nuclei of virtually all strains of Saccharomyces cerevisiae. The plasmid has no apparent phenotypic effect on host cells, and is the basis of many useful vectors for the transformation of yeast. Under certain circumstances, the plasmid is apparently able to replicate more than once per cell cycle; this over-replication allows the maintenance of the plasmid at high copy number. The plasmid has two inverted repeat sequences, and encodes a product that catalyses intramolecular recombination between these two repeats. Models are proposed whereby recombination leads to copy number amplification. In particular, it is proposed that intra-molecular recombination during replication flips the orientation of one replication fork with respect to the other, so that both forks travel in the same direction around a circular monomer template, generating a large multimer from a monomer and a single initiation of replication.