Biology subjects

Yeeles, J. T. P.

Publications and source records attributed to Yeeles, J. T. P..

3 recordsLinked to original sources

bioRxiv2026

MCM10 targets CMG dimers via a conserved mechanism for synchronized helicase activation

Activation of the CMG (CDC45-MCM-GINS) helicase by MCM10 is a central unresolved step in DNA replication. DNA is melted within a dimeric CMG complex and one strand is expelled from each topologically closed MCM ring. How MCM10 drives this process is unclear owing to a lack of structural information. Here, by determining structures of yeast CMG-Mcm10 complexes, and of human CMG-Pol {varepsilon} dimers assembled by DONSON and bound to MCM10 and the helicase activator RECQL4, we reveal a conserved mechanism of CMG helicase activation in eukaryotes. MCM10 targets CMG dimers through highly conserved and species-specific interactions, that in human also involve RECQL4. Our data indicate this arrangement allows MCM10 to stimulate DNA unwinding by CMG and to utilise the associated conformational changes to drive single-stranded DNA ejection between MCM2 and MCM5. This mechanism provides an explanation for synchronized activation of two CMG helicases at origins of bidirectional replication.

molecular biology↗

bioRxiv2023

CST--Polymeraseα-primase solves a second telomere end-replication problem

Telomerase adds G-rich telomeric repeats to the 3' ends of telomeres1, counteracting telomere shortening caused by loss of telomeric 3' overhangs during leading-strand DNA synthesis ("the end-replication problem"2). We report a second end-replication problem that originates from the incomplete duplication of the C-rich telomeric repeat strand by lagging-strand synthesis. This problem is solved by CST-Polymerase(Pol)-primase fill-in synthesis. In vitro, priming for lagging-strand DNA replication does not occur on the 3 overhang and lagging-strand synthesis stops in an [~]150-nt zone more than 26 nt from the end of the template. Consistent with the in vitro data, lagging-end telomeres of cells lacking CST-Pol-primase lost [~]50-60 nt of CCCTAA repeats per population doubling (PD). The C-strands of leading-end telomeres shortened by [~]100 nt/PD, reflecting the generation of 3 overhangs through resection. The measured overall C-strand shortening in absence of CST-Pol-primase fill-in is consistent with the combined effects of incomplete lagging-strand synthesis and 5' resection at the leading-ends. We conclude that canonical DNA replication creates two telomere end-replication problems that require telomerase to maintain the G-strand and CST-Pol-primase to maintain the C-strand.

cell biology↗

bioRxiv2019

Cryo-EM Structure of the Fork Protection Complex Bound to CMG at a Replication Fork

The eukaryotic replisome, organized around the Cdc45-MCM-GINS (CMG) helicase, orchestrates chromosome replication. Multiple factors associate directly with CMG including Ctf4 and the heterotrimeric fork protection complex (Csm3/Tof1 and Mrc1), that have important roles including aiding normal replication rates and stabilizing stalled forks. How these proteins interface with CMG to execute these functions is poorly understood. Here we present 3-3.5 [A] resolution cryo-EM structures comprising CMG, Ctf4, Csm3/Tof1 and Mrc1 at a replication fork. The structures provide high-resolution views of CMG:DNA interactions, revealing the mechanism of strand separation. Furthermore, they illustrate the topology of Mrc1 in the replisome and show Csm3/Tof1 grips duplex DNA ahead of CMG via a network of interactions that are important for efficient replication fork pausing. Our work reveals how four highly conserved replisome components collaborate with CMG to facilitate replisome progression and maintain genome stability.

biochemistry↗