Fol. Biol. 2011, 57, 3-11
A Fraction of MCM 2 Proteins Remain Associated with Replication Foci During a Major Part of S Phase
The essential role of MCM 2–7 proteins in the initiation of DNA replication in all eukaryotes is well known. Their role in replication elongation is supported by numerous studies, but there is still a knowledge gap in this respect. Even though biochemical studies have established an association of MCM proteins with replication forks, previous immunofluorescence studies in mammalian cells have suggested that MCM 2–7 proteins are displaced after replication initiation from sites of DNA replication. Therefore, we used a robust statistical method to more precisely analyse immunofluorescence localization of MCM 2 proteins with respect to the DNA replication foci. We show that despite the predominantly different localization of MCM 2 and replication signals, there is still a small but significant fraction of MCM 2 proteins that co-localize with DNA replication foci during most of S phase. The fluorescence localization of the MCM 2 proteins and DNA replication may thus reflect an active function of MCM 2 proteins associated with the replication foci and partially explain one facet of the “MCM paradox”.
Keywords
DNA replication, MCM proteins, immunofluorescence, replication foci, MCM paradox.
Funding
This work was supported by grants from the Deutsche Forschungsgemeinschaft and Bundesministerium für Bildung und Forschung (to M. C. C.), Czech grants MSM 0021620806, LC535 and AV0Z50110509 (to I. R.), and Grant 260501 from Charles University in Prague (to P. J.).
References
Copyright
This is an open-access article distributed under the terms of the Creative Commons Attribution License.
