Liang C, Weinreich M, Stillman B
Cold Spring Harbor Laboratory, New York 11724, USA.
Cell. 1995 Jun 2;81(5):667-76. doi: 10.1016/0092-8674(95)90528-6.
The origin recognition complex (ORC) binds replicators in the yeast S. cerevisiae in a manner consistent with it being an initiator protein for DNA replication. Two-dimensional (2D) gel techniques were used to examine directly initiation of chromosomal DNA replication in temperature-sensitive orc mutants. Unlike in wild-type cells, in orc2-1 and orc5-1 mutant cells, only a subset of replicators formed active origins of DNA replication at the permissive temperature. At the restrictive temperature, the number of active replicators was diminished further. Using a genetic screen, CDC6 was identified as a multicopy suppressor of orc5-1. 2D gel and biochemical analyses demonstrated that Cdc6p interacted functionally and physically with ORC. We suggest that ORC and Cdc6p form a prereplication complex at individual replicators and therefore cooperate to determine the frequency of initiation of DNA replication in the genome.
起源识别复合物（ORC）以一种与作为DNA复制起始蛋白相一致的方式结合酿酒酵母中的复制子。二维（2D）凝胶技术被用于直接检测温度敏感型orc突变体中染色体DNA复制的起始情况。与野生型细胞不同，在orc2-1和orc5-1突变体细胞中，只有一部分复制子在允许温度下形成了活跃的DNA复制起始位点。在限制温度下，活跃复制子的数量进一步减少。通过遗传筛选，CDC6被鉴定为orc5-1的多拷贝抑制因子。二维凝胶和生化分析表明，Cdc6p在功能和物理上与ORC相互作用。我们认为，ORC和Cdc6p在单个复制子处形成一个复制前复合物，因此协同作用以确定基因组中DNA复制起始的频率。
