Studies on the activator 1 protein complex, an accessory factor for proliferating cell nuclear antigen-dependent DNA polymerase delta.

摘要: Activator 1 (A1) is a multiprotein complex which essential for proliferating cell nuclear antigen (PCNA)-dependent DNA polymerase delta (pol delta) activity and efficient in vitro synthesis the SV40 dipolymerase replication system. In this report, we describe isolation of A1 from HeLa cytosolic extracts. stimulated pol singly primed phi X174 or (dA)4500.oligo(dT)12-18 reactions containing PCNA, single-stranded binding protein (SSB), ATP. Using assay, has been extensively purified. Purified preparations contained five discrete subunits 145, 40, 38, 37, 36.5 kDa. ATP hydrolysis to ADP Pi A1-dependent activity, have shown that contains an intrinsic ATPase by DNA. The DNA-dependent can be PCNA further activated plus human protein. These stimulatory effects were observed with (dA)4500.oligo(dT)12-18, but not detected each poly-deoxynucleotide alone. Furthermore, formed could measured nitrocellulose binding. No (dA)4500 oligo(dT)12-18 alone was procedure. Data are also presented indicate A1, conjunction functions as primer-recognition factor delta, increasing its ability utilize low levels primer ends, it does increase size products. markedly reduced amount required on multiply suggesting interacts at end. multiple closely resemble properties multisubunit RF-C described Tsurimoto Stillman (Tsurimoto, T., Stillman, B. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 1023-1027).