Li X, Burgers P M
Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110.
Proc Natl Acad Sci U S A. 1994 Feb 1;91(3):868-72. doi: 10.1073/pnas.91.3.868.
Yeast replication factor C (RF-C) is a multi-polypeptide complex required for processive DNA replication by DNA polymerases delta and epsilon. The gene encoding the 40-kDa subunit of the Saccharomyces cerevisiae RF-C (RFC3) has been cloned. The RFC3 gene is required for yeast cell growth and has been mapped to the left arm of chromosome XIV. The deduced amino acid sequence of the RFC3 gene shows a high homology to the 36-, 37-, and 40-kDa subunits of human RF-C (also called activator 1), with the highest homology to the 36-kDa subunit. Among the conserved regions are the A motif of ATP binding proteins; the "DEAD box," common to DNA helicases and other ATPases; and the "RFC box," an approximately 15-amino acid domain virtually identical in the yeast and human RF-C subunits. Limited homology to the functional homologs of the Escherichia coli replication apparatus was also observed. The steady-state mRNA levels of RFC3 do not change significantly during the mitotic cell cycle of yeast. The intact form of the RFC3 gene product (Rfc3p) has been overproduced in E. coli and purified to homogeneity. Purified Rfc3p has an ATPase activity that is markedly stimulated by single-stranded DNA but not by double-stranded DNA or RNA.
酵母复制因子C（RF-C）是DNA聚合酶δ和ε进行持续性DNA复制所必需的一种多亚基复合物。编码酿酒酵母RF-C 40-kDa亚基的基因（RFC3）已被克隆。RFC3基因是酵母细胞生长所必需的，并且已被定位到第十四条染色体的左臂。RFC3基因推导的氨基酸序列与人类RF-C（也称为激活因子1）的36-kDa、37-kDa和40-kDa亚基具有高度同源性，与36-kDa亚基的同源性最高。保守区域包括ATP结合蛋白的A基序；DNA解旋酶和其他ATP酶共有的“DEAD框”；以及“RFC框”，这是酵母和人类RF-C亚基中几乎相同的一个约15个氨基酸的结构域。还观察到与大肠杆菌复制装置功能同源物的有限同源性。在酵母的有丝分裂细胞周期中，RFC3的稳态mRNA水平没有显著变化。RFC3基因产物（Rfc3p）的完整形式已在大肠杆菌中过量表达并纯化至同质。纯化的Rfc3p具有ATP酶活性，该活性受到单链DNA的显著刺激，但不受双链DNA或RNA的刺激。
