The DNA replication stress response

Summary

Genome integrity in human cells is maintained through the coordinated functions of the DNA damage response. We study these processes with particular interest in the pathways that respond to telomere deprotection and replication stress in cancer cells.

Supervisor(s)

Dr Tony Cesare

Research Location

Westmead - Childrens Medical Research Institute

Program Type

PHD

Synopsis

Genome instability is a hallmark of nearly all solid tumors and adult-onset leukemias. It is now apparent that in the early stages of cancer development, genome instability is primarily caused by DNA "replication stress". Replication stress is broadly defined as perturbations in the dynamics of the replication machinery, characterized by slow progression of DNA replication forks, replication fork collapse, and activation of additional origins of DNA replication. Replication is frequently challenged through stresses originating exogenously (e.g. low nutrient environment, genotoxic agents) or endogenously (e.g. oncogene expression). In healthy cells, replication stress activates the DNA damage response (DDR) to induce growth arrest and tumor suppression. However, in the absence of functional tumor suppressor pathways, the DDR does not activate senescence and cells continue to proliferate desipite replication difficulties. For this reason, tumour cells typically display high levels of endogenous replication stress. This presents an opportunitstic target to induce cancer cell death by exploiting and endogenous weakness in the cancer cell. 
Replication stress has been associated with "mitotic catastrophe". Another broad descriptor that is used to explain mitotic cell death of an unexplained mechanism. Our laboratory has recently elucidated a mechanism of mitotic catastrophe in reponse to replication stress. Additionally, we identified a novel pathway where DNA replication stress alteres nuclear architecture to efficiently propagate repair. 
We are looking to expand on these discoveries in three directions: 1) Further elucidate how replication stress translates to mitotic cell death; 2) probe if mechanisms of cell death induced by chemotherapeutic replication stress inducing drugs are conserved; 3) understand how nuclear architecture is changed to enable repair of DNA replication stress in health cells. Opportunities are available in all three trajectories and projects will be tailored to applicant's interests and strengths on an individual basis.

Additional Information

Research approach, techniques and equipment
Our laboratory utilizes cutting edge cell and molecular biology techniques to study genome integrity in human cells, with a primary focus on DNA replication, telomere biology and the the DNA damage response. Much of our research uses advanced imaging platforms including spinning disk confocal and wide field live cell imaging systems, super resolution microscopy, and automated image capture and analysis. The lab also employs viral vector shRNA and CRISPR systems for modification of gene expression. This year we plan to embark on our first CRISPR screens. These research activities are supported by the internationally unique $2M Australian Cancer Research Foundation Telomere Analysis Centre (ATAC) located at CMRI and equipment in our laboratory. We are also always on the lookout for talented young individuals who can bring new experimental techniques to our lab. 
MethodologiesCell and Molecular Biology; Viral vector based gene expression modification (shRNA, CRISPR); CRISPR screen; Live cell imaging (widefield and confocal); Fixed imaging (confocal and widefield); Automated image capture and analysis; Super-resolution microscopy; Cell based assays to measure genome instability and viability; Flow cytometryStandard molecular biology and biochemistry (western blot, Chromatin Immunoprecipitation, etc); Mass-spectrometry (for selected students with interest and previous experience); DNA fiber analysis, ChIP and ChIP-seq (for selected students with interest and previous experience) 
PhD entry: Hons I classification, lab-based research experience is preferable. Our lab has a strict policy that all Ph.D. candidates must attract external funding (such as an APA, IPA, IPRS, etc).  

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Keywords

DNA replication stress, Cancer, genome stability, DNA damage response, chemotherapy, mitosis, mitotic catastrophe, ATR, CHK1, cohesion, chromosome dynamics, microscopy, Cell biology, molecular biology, live cell imaging, confocal microscopy, super resolution microscopy, DNA combing analysis, CRISPR screens, genome editing.

Opportunity ID

The opportunity ID for this research opportunity is: 2285

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