Dynamics of human replication factors in the elongation phase of DNA replication

• Published in: Nucleic acids research Vol. 35; no. 20; pp. 6904 - 6916
• Main Authors: Masuda, Yuji, Suzuki, Miki, Piao, Jinlian, Gu, Yongqing, Tsurimoto, Toshiki, Kamiya, Kenji
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.11.2007; Oxford Publishing Limited (England)
• Subjects: Bacteriophage M13 - genetics; DNA Polymerase III - metabolism; DNA Replication; DNA, Single-Stranded - metabolism; Humans; Nucleic Acid Enzymes; Proliferating Cell Nuclear Antigen - metabolism; Replication Protein C - metabolism
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/gkm822

In eukaryotic cells, DNA replication is carried out by coordinated actions of many proteins, including DNA polymerase δ (pol δ), replication factor C (RFC), proliferating cell nuclear antigen (PCNA) and replication protein A. Here we describe dynamic properties of these proteins in the elongation step on a single-stranded M13 template, providing evidence that pol δ has a distributive nature over the 7 kb of the M13 template, repeating a frequent dissociation-association cycle at growing 3'-hydroxyl ends. Some PCNA could remain at the primer terminus during this cycle, while the remainder slides out of the primer terminus or is unloaded once pol δ has dissociated. RFC remains around the primer terminus through the elongation phase, and could probably hold PCNA from which pol δ has detached, or reload PCNA from solution to restart DNA synthesis. Furthermore, we suggest that a subunit of pol δ, POLD3, plays a crucial role in the efficient recycling of PCNA during dissociation-association cycles of pol δ. Based on these observations, we propose a model for dynamic processes in elongation complexes.