How is chromosome replication temporally and spatially regulated during the cell cycle?
(C. Fernández Fernández)
We wish to understand how chromosome replication is regulated, so that it occurs during the appropriate period of the cell cycle (Fig.1) and at the right sub-cellular localization (Fig.3). We propose to characterize the multiple, often redundant, regulatory pathways that control the timing of the initiation of DNA replication, and to study their localization in C. crescentus cells.
We recently identified an important regulator of the activity of the DnaA protein, named HdaA. This protein is spatially associated with the replisome (Fig.3) and it inactivates DnaA when functioning as the initiator of chromosome replication. This mechanism restricts the initiation of chromosome replication to only once per cell cycle.
Figure 3: HdaA co-localizes with the β-clamp of the DNA polymerase (DnaN) in live C. crescentus cells. Time lapse experiment using DnaN-RFP and HdaA-GFP-expressing cells analysed by DIC and fluorescence microscopy.