Reynolds A E, Murray A W, Szostak J W
Department of Molecular Biology, Massachusetts General Hospital, Boston 02114.
Mol Cell Biol. 1987 Oct;7(10):3566-73. doi: 10.1128/mcb.7.10.3566-3573.1987.
We have examined the replication and segregation of the Saccharomyces cerevisiae 2 microns circle. The amplification of the plasmid at low copy numbers requires site-specific recombination between the 2 microns inverted repeat sequences catalyzed by the plasmid-encoded FLP gene. No other 2 microns gene products are required. The overexpression of FLP in a strain carrying endogenous 2 microns leads to uncontrolled plasmid replication, longer cell cycles, and cell death. Two different assays show that the level of Flp activity decreases with increasing 2 microns copy number. This regulation requires the products of the REP1 and REP2 genes. These gene products also act together to ensure that 2 microns molecules are randomly segregated between mother and daughter cells at cell division.
我们研究了酿酒酵母2μm 环状质粒的复制和分离。该质粒在低拷贝数下的扩增需要由质粒编码的FLP基因催化2μm反向重复序列之间的位点特异性重组。不需要其他2μm基因产物。在携带内源性2μm质粒的菌株中FLP的过表达会导致不受控制的质粒复制、更长的细胞周期和细胞死亡。两种不同的测定方法表明，Flp活性水平随2μm拷贝数的增加而降低。这种调控需要REP1和REP2基因的产物。这些基因产物还共同作用，以确保2μm分子在细胞分裂时在母细胞和子细胞之间随机分离。
