Yoshimochi Takehiro, Fujikane Ryosuke, Kawanami Miyuki, Matsunaga Fujihiko, Ishino Yoshizumi
Department of Genetic Resources Technology, Faculty of Agriculture, Kyushu University, 6-10-1 Fukuoka 812-8581, Japan.
Department of Genetic Resources Technology, Faculty of Agriculture, Kyushu University, 6-10-1 Fukuoka 812-8581, Japan; BIRD-Japan Science and Technology Agency, 6-10-1 Fukuoka 812-8581, Japan.
J Biol Chem. 2008 Jan 18;283(3):1601-1609. doi: 10.1074/jbc.M707654200. Epub 2007 Nov 5.
Pyrococcus furiosus, a hyperthermophilic Archaea, has homologs of the eukaryotic MCM (mini-chromosome maintenance) helicase and GINS complex. The MCM and GINS proteins are both essential factors to initiate DNA replication in eukaryotic cells. Many biochemical characterizations of the replication-related proteins have been reported, but it has not been proved that the homologs of each protein are also essential for replication in archaeal cells. Here, we demonstrated that the P. furiosus GINS complex interacts with P. furiosus MCM. A chromatin immunoprecipitation assay revealed that the GINS complex is detected preferentially at the oriC region on Pyrococcus chromosomal DNA during the exponential growth phase but not in the stationary phase. Furthermore, the GINS complex stimulates both the ATPase and DNA helicase activities of MCM in vitro. These results strongly suggest that the archaeal GINS is involved in both the initiation and elongation processes of DNA replication in P. furiosus, as observed in eukaryotic cells.
嗜热栖热菌，一种超嗜热古菌，拥有真核生物微小染色体维持（MCM）解旋酶和GINS复合物的同源物。MCM蛋白和GINS蛋白都是真核细胞中启动DNA复制的必需因子。关于复制相关蛋白的许多生化特性已有报道，但尚未证明每种蛋白的同源物对古菌细胞中的复制也是必需的。在此，我们证明了嗜热栖热菌GINS复合物与嗜热栖热菌MCM相互作用。染色质免疫沉淀试验表明，在指数生长期，GINS复合物优先在嗜热栖热菌染色体DNA的oriC区域被检测到，而在稳定期则未检测到。此外，GINS复合物在体外刺激MCM的ATP酶和DNA解旋酶活性。这些结果强烈表明，正如在真核细胞中观察到的那样，古菌GINS参与了嗜热栖热菌DNA复制的起始和延伸过程。
