PhD Researcher in Extrachromosomal DNA Dynamics and Cellular Rejuvenation (M/F)

Job Description

Thesis Subject

Objectives and Scientific Questions
How does genome instability remain confined to a single cell, and under what conditions can it be transmitted to subsequent generations? Extrachromosomal DNA (ecDNA) provides a particularly well-suited system to address this question, as it can arise stochastically, replicate independently, and segregate asymmetrically during cell division. In budding yeast, extrachromosomal ribosomal DNA circles accumulate in aging mother cells but are normally retained away from newly formed daughter cells. This asymmetry may preserve the rejuvenation of daughter cells.

This PhD project will determine whether the loss of daughter-cell rejuvenation results from the transmission of ecDNA by aged mother cells, the emergence of more general chromosomal instability, or a combination of both processes. The project will focus on the dynamics of ecDNA and its functional consequences during replicative aging in Saccharomyces cerevisiae.

Experimental and Quantitative Approach
The successful candidate will carry out an integrated project combining the following activities:
- Perform long-term microfluidic experiments and live-cell fluorescence microscopy;
- Implement yeast genetic approaches and inducible systems for ecDNA formation;
- Quantify the formation, amplification, retention, and transmission of ecDNA between mother and daughter cells;
- Directly measure daughter-cell rejuvenation and replicative lifespan;
- Characterize chromosome segregation using imaging and targeted genomic analyses;
- Develop and use automated methods for image analysis and cell-lineage tracking;
- Integrate experimental data through statistical analysis, probabilistic inference, and quantitative modeling.

The experimental work will be closely integrated with computational analysis and modeling. This organization will foster interactions between cell biology, genetics, quantitative microscopy, image analysis, and biophysics.

Scientific, Material, and Financial Resources
The PhD position and research activities are funded through the ANR REJUVENATE project. The microfluidic devices, microscopes for long-term quantitative imaging, and computational and image-analysis resources required for the project are operational within the research team and its host environment.
The successful candidate will have access to a dedicated workstation, the project's equipment and consumables, as well as regular experimental and quantitative supervision.

Dissemination and Research Outputs
The results will be disseminated through the PhD thesis, presentations at scientific conferences, and the preparation of articles for publication in international peer-reviewed journals. The analytical methods and computational tools developed during the project will be documented and shared in accordance with the project's requirements, open-science principles, and intellectual property regulations.

References
Morlot S. et al. Cell Reports 28, 408–422.e4 (2019).
Aspert T. et al. eLife 11 (2022).
Malyavko A. et al. bioRxiv 2026.03.20.713207 (2026).

Your Work Environment

The CNRS is a French multidisciplinary public research organization. The PhD thesis will be carried out at the Biotechnology and Cell Signaling Laboratory (BSC, UMR 7242), a joint research unit of the CNRS and the University of Strasbourg, which also hosts a research team accredited by Inserm.

The unit, which comprises more than 50 full-time equivalent staff members, excluding trainees, conducts research at the interface between functional genomics and biological chemistry. It is located on the premises of the Strasbourg Graduate School of Biotechnology (ESBS), on the Illkirch-Graffenstaden campus.

The successful candidate will join the research team led by Gilles Charvin. The team brings together expertise in yeast genetics, microfluidics, quantitative microscopy, automated image analysis, statistical physics, and mathematical modeling. The research will be conducted in close interaction with the other teams within the BSC and with the technological platforms available on the campus.

The PhD will be registered at the University of Strasbourg and affiliated with the Doctoral School of Life and Health Sciences (ED 414), in the field of Molecular and Cellular Aspects of Biology. The doctoral training program will complement the scientific supervision provided by the laboratory.

The campus is accessible by public transportation and offers catering facilities. CNRS social benefits and partial reimbursement of public transportation subscriptions apply in accordance with the regulations in force.

Constraints and risks

- The project involves experimental work on site, including the handling of yeast strains, molecular biology reagents, and the use of fluorescence microscopes. All required safety training and laboratory procedures must be followed.

- Long-term acquisitions using microfluidic devices require careful planning of experiments and monitoring of the equipment.

- A significant part of the work will involve image and data analysis on a computer.

- Occasional travel in France or abroad may be required for conferences, training courses, or scientific collaborations.

- Recruitment is subject to admission to and enrollment in Doctoral School ED 414, as well as completion of the required administrative procedures.

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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