Architecture of the Saccharomyces cerevisiae Replisome

Abstract

Eukaryotic replication proteins are highly conserved, and thus study of Saccharomyces cerevisiae replication can inform about this central process in higher eukaryotes including humans. The S. cerevisiae replisome is a large and dynamic assembly comprised of ~50 proteins. The core of the replisome is composed of 31 different proteins including the 11-subunit CMG helicase; RFC clamp loader pentamer; PCNA clamp; the heteroligomeric DNA polymerases ε, δ, and α-primase; and the RPA heterotrimeric single strand binding protein. Many additional protein factors either travel with or transiently associate with these replisome proteins at particular times during replication. In this chapter, we summarize several recent structural studies on the S. cerevisiae replisome and its subassemblies using single particle electron microscopy and X-ray crystallography. These recent structural studies have outlined the overall architecture of a core replisome subassembly and shed new light on the mechanism of eukaryotic replication.

Too Much of a Good Thing: How Ectopic DNA Replication Affects Bacterial Replication Dynamics

“…This hypothesis might help to explain why a transition from strictly single to both single and multiple origins took place in archaea. In both archaea and eukaryotic cells, the replicative helicase has the opposite polarity to the replicative helicase in bacteria (Tuteja and Tuteja, 2004;Onesti, 2008, 2009;Sakakibara et al, 2009) and encircles the single stranded leading strand template (Bai et al, 2017). Okazaki fragments in eukaryotes are much shorter than in prokaryotes (Burgers, 2009), allowing the replicative helicase to simply unwind either one or perhaps even more un-ligated Okazaki fragments.…”

DONSON and FANCM associate with different replisomes distinguished by replication timing and chromatin domain

“…ukaryotic replisomes are multiprotein complexes consisting, minimally, of the CMG helicase [MCM2-7 (M), CDC45 (C), and GINS (go, ichi, ni, san) proteins (G)], which forms a ring around the leading strand template. Other components include the pol α, ε, and δ polymerases, MCM10, and a few accessory factors [1][2][3][4][5][6][7] . The identification and characterization of the minimal components of biochemically active replisomes, the result of decades of extraordinary work from multiple laboratories, necessarily reflects studies with deproteinized model DNA substrates under carefully controlled conditions.…”

DNA Replication Through Strand Displacement During Lagging Strand DNA Synthesis in Saccharomyces cerevisiae

“…With the scope of introducing the proteins involved in lagging strand DNA synthesis in the context of the replication fork and replisome, we begin with a brief introduction of DNA replication initiation. However, due to the limited extent of this introduction, we re-direct readers interested in the mechanisms and regulations of DNA replication origin activation, replisome assembly and structure to recent reviews on this topic [ 1 , 2 , 3 , 4 ]. DNA replication initiates from specific regions on the chromosomes, known as origins of replication, which are well defined in Saccharomyces cerevisiae by the presence of an autonomously replicating sequence (ARS), but are less defined in vertebrates [ 3 , 5 , 6 , 7 , 8 ].…”