Mekanismen bakom replikationsinitiering - En genom-sökning
Tidsperiod: 2018-12-01 till 2021-12-31
Projektledare: Johan Elf
Budget: 3 900 000 SEK
At the core of this project is the question how a cell coordinates growth with DNA replication. We have recently shown that the bacterium E. coli does this by triggering replication initiation at a fixed volume per chromosome independent of growth rate. It is however not known how the bacterial cell, or any other cell, measures its volume. In fact, we find that the bacterial cell can determine the initiation volume at much higher precision than any of the previously proposed mechanisms for control of replication initiation would allow. The high precision severely limits the possible mechanisms for size sensing and it is clear that we are missing key players in the cell’s control system. To find these missing components we will use a new type of genetic screen where we can measure the replication initiation volume at the single-cell level in thousands of strains in parallel. The method depends on our unique combination of genetic engineering, microfluidics, and single molecule imaging that enables us to do large-scale phenotyping and genotyping in one experiment. The size-sensing quest is the first application of this powerful imaging method, but the technique holds great promise for all of cell biology. We will investigate coordination of DNA replication and growth in a bacterial system, but striking seminaries are seen in yeast and higher eukaryotes, where the mechanisms for size sensing in the G1/S transition is still unclear despite its importance for disease.