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

Michele Giannattasio,Dana Branzei

doi:10.3390/genes10020167

Abstract

This review discusses a set of experimental results that support the existence of extended strand displacement events during budding yeast lagging strand DNA synthesis. Starting from introducing the mechanisms and factors involved in leading and lagging strand DNA synthesis and some aspects of the architecture of the eukaryotic replisome, we discuss studies on bacterial, bacteriophage and viral DNA polymerases with potent strand displacement activities. We describe proposed pathways of Okazaki fragment processing via short and long flaps, with a focus on experimental results obtained in Saccharomyces cerevisiae that suggest the existence of frequent and extended strand displacement events during eukaryotic lagging strand DNA synthesis, and comment on their implications for genome integrity.

Highlights

This review discusses a set of experimental results that support the existence of extended strand displacement events during budding yeast lagging strand DNA synthesis
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
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]

Summary

The Replication Fork and the DNA Synthesis Apparatus

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. Phosphorylated MCM acts together with CDK-phosphorylated Sld and Sld to trigger the recruitment of firing factors, which remodel the MCM double hexamer to form the CMG helicase [5]. How this remodeling occurs is not fully understood [14]. Ctf is dispensable for Pol α-Primase -mediated priming Rather, it seems that Ctf is important for the newly replicated lagging strand filament [20]. DNA polymerase δ is recruited to the replisome parental histones transfer to the newly replicated lagging strand filament [20].

Schematic structure ofofthe the DNA

Possible mechanismsofofOkazaki