Project description:Cdc7 kinase is known to initiate DNA replication, but it is unknown where Cdc7 is found within the genome. We modified the Calling Cards method that uses the Ty5 retrotransposon to investigate Cdc7 binding in the genome. The Ty5 retrotransposon is inserted into the genome by DNA transcription factors or replication factors binding within the genome. We find that Cdc7 inserts Ty5 transposons throughout chromosomes and furthermore creates more Ty5 insertions into regions of DNA that are known to replicate early. Cdc7 does not solely integrate Ty5 at origins or replication, but rather throughout the genome.
Project description:In eukaryotes, CDC7 kinase is crucial for DNA replication initiation and has been involved in fork processing and replication stress response. Human CDC7 requires the binding of either one of two regulatory subunits, DBF4 and DRF1, for its activity. However, it is unclear whether the two regulatory subunits target CDC7 to a specific set of substrates, thus having different biological functions, or if they act redundantly. Using genome editing technology, we generated an isogenic set of cell lines deficient in either one of the two CDC7-activating subunits: these cells are viable but present signs of genomic instability, indicating that both DBF4 and DRF1 can independently support CDC7 for bulk DNA replication. Nonetheless, DBF4-deficient cells show altered replication efficiency, including partial deficiency in MCM helicase phosphorylation and alterations in the replication timing of discrete genomic regions. Notably, we find that CDC7 function at replication forks is entirely dependent on DBF4 and not DRF1. Thus, DBF4 is the primary regulator of CDC7 activity, likely mediating most of its functions in unperturbed DNA replication and during replication fork processing upon replication interference.
Project description:CDC7 is a serine-threonine kinase, which has an important role in the activation of replication origins in the S-phase. CDC7 is also a potential molecular target for the development of anticancer drugs. Multiple studies have shown that different cell lines have a wide range of sensitivity to CDC7 inhibition. However, how the manner in which cells respond to prolonged CDC7 inhibition has yet to be investigated. Hence, we performed an RNA-sequencing experiment to investigate variation in gene expression in cells undergoing prolonged CDC7 inhibition.
