Initiation of chromosomal DNA replication in eukaryotic cells; contribution of yeast genetics to the elucidation

Abstract

Chromosomal DNA replication is a fundamental process in the transmission of genetic information through generations. While the molecular mechanism of DNA replication has been studied for a long time, knowledge regarding this process in eukaryotic cells has advanced rapidly in the past 20 years. Yeast genetics contributed profoundly to this rapid advancement. Reverse genetics and genetic screenings identified all genes encoding replication proteins in budding yeast. Moreover, the genetic interactions that were used in screenings and analyses provided an insight into the molecular mechanism of chromosomal DNA replication. Further studies showed that complicated but sophisticated mechanisms govern chromosomal DNA replication. The retrospective view of the genetic approaches used to elucidate DNA replication in eukaryotes, together with current knowledge, tell us the reasons why some of the genetic screenings are successful, and also provide ideas for future directions.

Interaction between human Ctf4 and the Cdc45/Mcm2-7/GINS (CMG) replicative helicase

“…At the G1/S transition, this prereplication complex is altered further by a number of replication initiation factors whose actions are facilitated by the cyclin-dependent and cell division cycle 7 (Cdc7)-dumbbell former 4 (Dbf4) kinases (4). These replication initiation factors [which include synthetically lethal with dpb11-1 (Sld)2, Sld3, Sld7, DNA polymerase B possible subunit 11 (Dpb11), and DNA polymerase e (Pol e) in budding yeast] play critical roles resulting in the interaction of Cdc45 and GINS with the Mcm2-7 complex and the formation of the replicative DNA helicase complex containing Cdc45/Mcm2-7/GINS (CMG) (5). Other replication factors (including Mcm10 and Ctf4) contribute to the activation of the CMG helicase and association of proteins that recruit the replicative Pols to effect DNA replication (6,7).…”

Binding of MCM-interacting proteins to ATP-binding site in MCM6

“…[1][2][3][4] The function of MCM2-7 is regulated by various proteins. CDC45 binds to MCM2-7 with GINS complex to form CMG complex, and the cumulative data suggest that the CMG complex functions as a DNA helicase at the forks.…”

Evolutionary conservation of the CDK targets in eukaryotic DNA replication initiation

“…Our understanding of the role of CDK in replication initiation was greatly advanced by synthetic lethal genetic screens conducted by H. Araki and colleagues in the budding yeast Saccharomyces cerevisiae (Araki 2011;Kamimura et al 1998;. These screens utilised hypomorphic alleles of an essential replication factor called Dpb11, which has four BRCA1 C terminus (BRCT) repeats that act as phosphopeptide-binding domains.…”

“…These screens utilised hypomorphic alleles of an essential replication factor called Dpb11, which has four BRCA1 C terminus (BRCT) repeats that act as phosphopeptide-binding domains. From these synthetic lethal with dpb11 (SLD) screens, several new replication factors were identified, including two genes SLD2 and SLD3 (Araki 2011). Subsequent studies showed that both Sld2 and Sld3 are essential targets of CDK in budding yeast (Masumoto et al 2002;Tanaka et al 2007;Zegerman and Diffley 2007).…”