Non-Homologous End-Joining
Dik van Gent
Group leader: Dik van Gent
Group members: Ricardo Leite and Taka Inagawa (postdoc), Nicole Verkaik (technician), Isabel Jerchel (MSc student)
The group studies various aspects of DNA double strand break repair, with an emphasis on the non-homologous end-joining pathway. We address the complexity of this DNA repair pathway at the levels of biochemistry, cell biology, genetics and animal models. In collaboration with the Department of Immunology (Prof. Jacques van Dongen and Dr. Mirjam van der Burg) we also investigate defects in this DNA repair pathway in Severe Combined Immunodeficiency patients.
In addition to investigating the end-joining mechanism, we are also interested in the crosstalk within the DNA damage response. We are especially interested in factors that influence the choice of double strand break repair pathway (non-homologous end-joining or homologous recombination) and the interplay with other processes in the DNA damage response, such as cell cycle checkpoints and apoptosis induction. We study this both in the context of cells in culture and in tissues and tumours.
Specific research projects:
1. Mechanism of NHEJ (Taka Inagawa)
We investigate the composition and function of NHEJ complexes assembled on DNA ends. At this moment we study this subject primarily using purified proteins. We are especially interested in the dynamics of assembly and disassembly of NHEJ complexes and how various events, such as DNA-PK autophosphorylation, influence these dynamics. The ultimate goal is to understand all factors involved in complex assembly and function and to extrapolate the in vitro results to the in vivo situation, using live cell microscopy techniques.
2. Crosstalk between NHEJ and other elements of the DNA damage response (Ricardo Leite, Nicole Verkaik)
We investigate how NHEJ interacts with other DNA damage response pathways to counteract the negative consequences of DNA double strand breaks (e.g. after gamma-irradiation). We are currently mainly interested in the role of microRNA responses in regulating various elements of the DNA damage response after ionizing radiation. We identified microRNA regulation of several processes, including cell cycle regulation and apoptosis.
3. NHEJ defects and SCID (Isabel Jerchel, in collaboration with Hanna IJspeert and Mirjam van der Burg, Immunology)
We investigate the genetic defects in Severe Combined Immunodeficiency (SCID) patients, especially in radiosensitive patients. We have identified and characterized defects in the Artemis, ligase IV, DNA-PKcs and Xlf/Cernunnos genes. We are committed to solve the underlying defect in these patients in molecular detail, including understanding of the molecular mechanisms leading to the patient phenotype caused by non-null mutations in these genes.
4. DNA damage responses in tissues and tumours (Nicole Verkaik, Alex Zelensky)
We are currently starting a new project to study DNA damage responses in cells within tissues and tumours. In collaboration with the Departments of Internal Oncology and Pathology we develop novel techniques to study DNA repair, cell cycle checkpoint activation and apoptosis in living breast and ovarian tumour slices, with the ultimate goal to develop methods to predict treatment response in the tumour. The primary focus is at this moment on tumour sensitivity to PARP inhibitors, which are in clinical trials for hereditary breast and ovarian cancer, but may also be useful for treatment of sporadic tumours.
Contact information:
Dr. Dik C. van Gent
Dept. of Genetics
Erasmus MC
PO Box 2040
3000 CA Rotterdam
The Netherlands
Tel. +31-10-7043932
FAX: +31-10-7044743
e-mail: d.vangent@erasmusmc.nl