Leatherwood J, Lopez-Girona A, Russell P
Department of Molecular Biology, Scripps Research Institute, La Jolla, California 92037, USA.
Nature. 1996 Jan 25;379(6563):360-3. doi: 10.1038/379360a0.
In fission yeast, Cdc2 kinase has both positive and negative roles in regulating DNA replication, being first necessary for the transition from G1 to S phase and later required to prevent the re-initiation of DNA replication during G2. We report here that Cdc2 interacts with Orp2, a protein similar to the Orc2 replication factor subunit of Saccharomyces cerevisiae origin recognition complex (ORC). ORC binds chromosomal origins and is essential for chromosomal replication initiation. Fission yeast Orp2 is required for DNA replication and interacts with the rate-limiting replication activator Cdc18. Cells lacking Orp2 undergo aberrant mitosis, indicating that Orp2 is involved in generating a checkpoint signal. These findings suggest that ORC functions are conserved among eukaryotes and provide evidence that Cdc2 controls DNA replication initiation by acting directly at chromosomal origins.
在裂殖酵母中，Cdc2激酶在调节DNA复制过程中具有正负两方面的作用，它首先是从G1期过渡到S期所必需的，随后则是在G2期防止DNA复制重新启动所必需的。我们在此报告，Cdc2与Orp2相互作用，Orp2是一种类似于酿酒酵母起始识别复合物（ORC）的Orc2复制因子亚基的蛋白质。ORC结合染色体起始位点，对染色体复制起始至关重要。裂殖酵母中的Orp2是DNA复制所必需的，并与限速复制激活因子Cdc18相互作用。缺乏Orp2的细胞会经历异常有丝分裂，这表明Orp2参与产生一个检查点信号。这些发现表明ORC的功能在真核生物中是保守的，并提供了证据证明Cdc2通过直接作用于染色体起始位点来控制DNA复制起始。
