| 1. |
Tatsuro Takahashi, Dale B. Wigley, Johannes C. Walter, Pumps, paradoxes and ploughshares
Mechanism of the MCM2-7 DNA helicase, Trends in Biochemical Sciences, 10.1016/j.tibs.2005.06.007, 2005.08, In eukaryotes, numerous lines of evidence have coalesced into a convincing case that the MCM2-7 complex - a heterohexameric ATPase - is the replicative DNA helicase. However, almost nothing is known about how this enzyme functions in a cellular context. Some models for the mechanism of the MCM2-7 helicase envision that it translocates along single-stranded DNA (ssDNA), whereas, more recently, it is has been suggested that it pumps double-stranded DNA (dsDNA) through its central channel. In particular, one model in which a double hexamer of MCM2-7 pumps dsDNA towards the hexamer interface and extrudes ssDNA laterally as a result of torsional strain is gaining popularity. Here, we discuss existing models and propose a new variation in which a single hexamer is the functional unit of the helicase. Duplex DNA is pumped into MCM2-7 and, as it emerges from the complex, a rigid protein that we term the 'ploughshare' splits the duplex.. |
| 2. |
Rebecca Sherwood, Tatsuro Takahashi, Prasad V. Jallepalli, Sister acts
Coordinating DNA replication and cohesion establishment, Genes and Development, 10.1101/gad.1976710, 2010.12, The ring-shaped cohesin complex links sister chromatids and plays crucial roles in homologous recombination and mitotic chromosome segregation. In cycling cells, cohesin's ability to generate cohesive linkages is restricted to S phase and depends on loading and establishment factors that are intimately connected to DNA replication. Here we review how cohesin is regulated by the replication machinery, as well as recent evidence that cohesin itself influences how chromosomes are replicated.. |
