Live-cell imaging of DNA replication at replication factories. (360G-Wellcome-080737_Z_06_Z)

WT Studentship for Miss Nazan Saner: 4-year PhD studentship in Molecular and Cellular Biology Replication of DNA is initiated from defined origins on chromosomes and proceeds with replication forks travelling bi-directionally from the origins. The timing of DNA replication initiation from various origins is highly coordinated; some origins fire early and others late during S phase. Moreover, inside nuclei, the bulk of DNA replication is physically organized in replication factories, intranuclear foci consisting of DNA polymerases and other replication proteins. Each factory processes several (2-100) active replication forks. The adjacent replicons along a chromosome might be organized for replication in the same replication factory. However, it is not yet clear what determines the groups of replicons that replicate at individual replication factories. We have been studying duplication of chromosomal DNA using budding yeast Saccharomycces cerevisiae as a model organism. Many basic mechanisms of DNA replication are similar in yeast and human cells. It is therefore likely that results form the yeast system will be of direct relevance to DNA replication mechanisms in human cells. In budding yeast, we can utilize amenable genetics and advanced knowledge in proteomics. In particular, the location of replication origins on chromosomes and the time of their firing have been well studied in this organism. We propose to investigate the spatial and temporal organization of DNA replication in budding yeast using a range of live-cell imaging techniques that have been recently developed in the lab. In particular, we will address which groups of replicons are processed in individual replication factories, how this grouping is determined and how this process is organized.