Mcm10 Plays a Role in Functioning of the Eukaryotic Replicative DNA Helicase, Cdc45-Mcm-GINS

Watase, George J.; Takisawa, Haruhiko; Kanemaki, Masato T.

doi:10.1016/j.cub.2012.01.023

Cited by 104 publications

(149 citation statements)

References 42 publications

Supporting

Mentioning

127

Contrasting

Order By: Relevance

“…The CMG-ssDNA structure shows a very different configuration of the WHD modules, and indicates that upon ssDNA binding, the Mcm5-WHD moves out of the central channel and becomes disordered, the Mcm6-WHD moves backward and away from the channel, and the Mcm4-WHD now partially occludes the channel opening. These changes make it likely that CMG can encircle dsDNA, consistent with reports demonstrating that Mcm2-7 matures into two fully assembled CMGs on dsDNA before origin DNA unwinding occurs (22)(23)(24)(25).…”

Section: Resultssupporting

confidence: 86%

“…The Mcm2-7 double hexamer is oriented head-to-head (N terminus to N terminus) in the PreRC during the G1 phase. In the S phase the Mcm2-7 double hexamer matures into head-tohead CMGs at the origin before ssDNA is generated (22)(23)(24)(25). The two CMGs at the origin eventually separate because individual replication forks contain just one CMG (39,40).…”

Section: Implications Of N-tier Ahead Of C-tier During Cmg Translocatmentioning

confidence: 99%

See 1 more Smart Citation

Structure of eukaryotic CMG helicase at a replication fork and implications to replisome architecture and origin initiation

Georgescu

Yuan

Bai

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

189

299

View full text Add to dashboard Cite

The eukaryotic CMG (Cdc45, Mcm2-7, GINS) helicase consists of the Mcm2-7 hexameric ring along with five accessory factors. The Mcm2-7 heterohexamer, like other hexameric helicases, is shaped like a ring with two tiers, an N-tier ring composed of the N-terminal domains, and a C-tier of C-terminal domains; the C-tier contains the motor. In principle, either tier could translocate ahead of the other during movement on DNA. We have used cryo-EM single-particle 3D reconstruction to solve the structure of CMG in complex with a DNA fork. The duplex stem penetrates into the central channel of the N-tier and the unwound leading single-strand DNA traverses the channel through the N-tier into the C-tier motor, 5′-3′ through CMG. Therefore, the N-tier ring is pushed ahead by the C-tier ring during CMG translocation, opposite the currently accepted polarity. The polarity of the N-tier ahead of the C-tier places the leading Pol e below CMG and Pol α-primase at the top of CMG at the replication fork. Surprisingly, the new N-tier to C-tier polarity of translocation reveals an unforeseen quality-control mechanism at the origin. Thus, upon assembly of head-to-head CMGs that encircle doublestranded DNA at the origin, the two CMGs must pass one another to leave the origin and both must remodel onto opposite strands of single-stranded DNA to do so. We propose that head-to-head motors may generate energy that underlies initial melting at the origin.CMG helicase | DNA replication | DNA polymerase | origin initiation | replisome R eplicative helicases are hexameric rings in all domains of life (1-3). In bacteria and archaea, the replicative helicase is a homohexamer and encircles single-strand (ss) DNA at a replication fork. Some viral and phage replicative helicases are also ring-shaped hexamers, including bovine papilloma virus (BPV) E1, simian virus 40 (SV40) large T-antigen (T-Ag), and the T4 and T7 phage helicases. Unlike other replicative helicases, the eukaryotic replicative Mcm2-7 helicase is composed of six nonidentical but homologous Mcm subunits that become activated upon assembly with five accessory factors (Cdc45 and GINS tetramer) to form the 11-subunit CMG (Cdc45, Mcm2-7, GINS) (4-6). Numerous studies have outlined the process that forms CMG at origins in which the Mcm2-7 heterohexamer is loaded onto DNA as an inactive double hexamer in G1 phase, and becomes activated in S phase by several initiation proteins and cell-cycle kinases that assemble Cdc45 and GINS onto Mcm2-7 to form the active CMG helicases (7-9).Helicases assort into six superfamilies (SF1-SF6) based on sequence alignments (10). The SF1 and SF2 helicases are generally monomeric and the SF3-SF6 helicases are hexameric rings used in DNA replication and other processes. The bacterial SF4 and SF5 helicases contain RecA-based motors and translocate 5′-3′, whereas the eukarytic SF3 and SF6 helicases contain AAA+ (ATPases associated with diverse cellular activities)-based motors and translocate 3′-5′ (3, 10). Examples of well-studied hexameric helicases include t...

show abstract

Section: Resultssupporting

confidence: 86%

Section: Implications Of N-tier Ahead Of C-tier During Cmg Translocatmentioning

confidence: 99%

Structure of eukaryotic CMG helicase at a replication fork and implications to replisome architecture and origin initiation

Georgescu

Yuan

Bai

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

189

299

View full text Add to dashboard Cite

show abstract

“…Mcm10 is not required for the loading of Pol 1 in vitro, because Pol 1 is loaded to origins as a component of the pre-LC (Muramatsu et al 2010;Heller et al 2011). Recent in vivo studies indicate that Mcm10 is required for the unwinding of origin DNA and further loading of Pol a to origins after Cdc45, Mcm2 -7, and GINS form a complex van Deursen et al 2012;Watase et al 2012). Because CDK and DDK are required for the activation of the replicative helicase, the question of whether CMG formation is sufficient for the loading of Mcm10 is intriguing.…”

Section: Subsequent Eventsmentioning

confidence: 99%

Helicase Activation and Establishment of Replication Forks at Chromosomal Origins of Replication

Tanaka

Araki

2013

Cold Spring Harbor Perspectives in Biology

160

146

View full text Add to dashboard Cite

Many replication proteins assemble on the pre-RC-formed replication origins and constitute the pre-initiation complex ( pre-IC). This complex formation facilitates the conversion of Mcm2-7 in the pre-RC to an active DNA helicase, the Cdc45-Mcm-GINS (CMG) complex. Two protein kinases, cyclin-dependent kinase (CDK) and Dbf4-dependent kinase (DDK), work to complete the formation of the pre-IC. Each kinase is responsible for a distinct step of the process in yeast; Cdc45 associates with origins in a DDK-dependent manner, whereas the association of GINS with origins depends on CDK. These associations with origins also require specific initiation proteins: Sld3 for Cdc45; and Dpb11, Sld2, and Sld3 for GINS. Functional homologs of these proteins exist in metazoa, although pre-IC formation cannot be separated by requirement of DDK and CDK because of experimental limitations. Once the replicative helicase is activated, the origin DNA is unwound, and bidirectional replication forks are established.

show abstract

“…[57][58][59] [64][65][66] These recent reports suggest that Mcm10 plays a role in activating the fully-assembled CMG. It may be that both models are correct; in other words, Mcm10 may have multiple functions in replication initiation.…”

mentioning

confidence: 89%

Insights into the Initiation of Eukaryotic DNA Replication

Bruck¹,

Pérez-Arnaiz

Colbert

et al. 2015

Nucleus

View full text Add to dashboard Cite

Mcm10 Plays a Role in Functioning of the Eukaryotic Replicative DNA Helicase, Cdc45-Mcm-GINS

Cited by 104 publications

References 42 publications

Structure of eukaryotic CMG helicase at a replication fork and implications to replisome architecture and origin initiation

Structure of eukaryotic CMG helicase at a replication fork and implications to replisome architecture and origin initiation

Helicase Activation and Establishment of Replication Forks at Chromosomal Origins of Replication

Insights into the Initiation of Eukaryotic DNA Replication

Contact Info

Product

Resources

About