Eukaryotic DNA Replication Fork

Abstract

This review focuses on the biogenesis and composition of the eukaryotic DNA replication fork, with an emphasis on the enzymes that synthesize DNA and repair discontinuities on the lagging strand of the replication fork. Physical and genetic methodologies aimed at understanding these processes are discussed. The preponderance of evidence supports a model in which DNA polymerase ε (Pol ε) carries out the bulk of leading strand DNA synthesis at an undisturbed replication fork. DNA polymerases α and β carry out the initiation of Okazaki fragment synthesis and its elongation and maturation, respectively. This review also discusses alternative proposals, including cellular processes during which alternative forks may be utilized, and new biochemical studies with purified proteins that are aimed at reconstituting leading and lagging strand DNA synthesis separately and as an integrated replication fork.

Translesion and Repair DNA Polymerases: Diverse Structure and Mechanism

“…The finger domain, which interacts with a nascent base pair, has varied sequences and contributes to different lesion preferences and biased dNTP selection. Despite the lack of finger-domain movement, the Little Finger domain (LF) may be flexible, and a semi-detached LF in the DINB branch of Y polymerases creates a structural gap capable of accommodating bulky aromatic adducts and inducing frameshift mutations (73–77) (Fig. 4b).…”

The small subunit of DNA polymerase D (DP1) associates with GINS–GAN complex of the thermophilic archaea in Thermococcus sp. 4557

“…In eukaryotes, replication of the nuclear genome is largely conducted by three members of the B family of DNA polymerases, polymerases α, ε, and δ (Pols α, ε, and δ, respectively). Polymerase α mainly synthesizes short RNA–DNA primers to initiate replication, while Pols ε and δ are responsible for DNA chain elongation (Bell & Labib, ; Burgers & Kunkel, ; M. A. Garbacz et al, ; Lujan, Williams, & Kunkel, ; Stodola & Burgers, ). One model supports that Pol ε replicates the leading DNA strand, while the lagging strand is primarily conducted by Pol δ.…”

Evolutionary dynamics and significance of multiple subclonal mutations in cancer

“…It was postulated that amongst the earliest molecular events that initiated transformation of normal cells into premalignant cells was damage to critical genes required for maintaining genetic stability. The initial focus was on replicative DNA polymerases (Pol-α, -δ, and -ε) [13]; these enzymes are responsible for the accurate copying of some 6 billion nucleotides during each division cycle. Single amino acid substitutions in their catalytic sites result in increased errors in nucleotide incorporation.…”

“…The accuracy of DNA replication also depends on both initial conformational recognition of correct base-pairs by the polymerase active site and subsequent proofreading steps [11–13]. The work of Sam Wilson established alterations in the structure of DNA polymerase β at the template-binding site as it encounters complementary or non-complementary nucleotides [14].…”