DNA Damage & Repair (DDR)

Equipe de recherche
RESPONSABLE
Joanna TIMMINS
joanna.timmins@ibs.fr
+33 (0) 4 57 42 86 78I

CHAMPS D’EXPERTISE

DNA repair; Nucleoid organisation; Anti-cancer drug resistance; Protein-protein inhibitors; FRET; Fluorescence imaging; Structural Biology; Biochemistry

ACTIVITES DE RECHERCHE / SERVICES

The prime objective for every life form is to deliver its genetic material, intact and unchanged, to the next generation, despite constant assaults from both endogenous and environmental sources on the DNA. DNA lesions can block genome replication and transcription, and if left unrepaired can lead to mutations or wider-scale genome aberrations that threaten cell or organism viability. To counter this threat, cells have evolved several elaborate DNA damage response systems.

Research projects

1.Our team studies the molecular mechanisms underlying DNA damage recognition and repair in the radiation-resistant bacterium Deinococcus radiodurans. Our work focuses on two major aspects, which are:

  • Dynamics of DNA Damage Repair Processes
  • Recognition of DNA Lesions

Our goal is to use a combination of Structural Biology methods and Biophysical and Biochemical tools to decipher the complex molecular processes leading to efficient repair of DNA lesions

2. Our team also studies the organisation and dynamics of Deinococcus radiodurans nucleoids that present several unusual features: they adopt a toroidal shape and are highly condensed.
Here our goal is to use structural biology and biochemical approaches together with live cell imaging techniques (conventional and super resolution PALM/PAINT fluorescence microscopy) to better understand the mechanisms underlying nucleoid organisation and chromosome segregation during the cell cycle.

3. Our team also studies DNA repair enzymes from humans and in particular we are studying the interaction between a DNA glycosylase, hNTH1, and a transcription factor, YB1. This complex is involved in anti-cancer drug resistance in solid tumours treated with cisplatin. In order to identify potential inhibitors of this complex, which could be used to resensitize drug-resistant tumour cells, we have developed a highly effective and low-cost FRET-based biosensor in order to perform high-throughput screening of chemical libraries.

Expertise in oncology: DNA repair expert & solid experience in the study of protein-DNA and protein-protein interactions using diverse biochemical and biophysical approaches.

COMPETENCES / MOYENS TECHNIQUES

Methodologies:

  • Structural Biology: Expression and purification of proteins, X-ray crystallography and small-angle X-ray scattering of proteins and protein-DNA complexes.
  • Biochemistry: Development of in vitro DNA repair assays for Base excision repair enzymes and nucleotide excision repair proteins using purified proteins and fluorescently tagged DNA probes.
  • Biophysics: Use of biophysical approaches (thermal shift assay, isothermal titration calorimetry, surface plasmon resonance, electrophoretic mobility shift assays, AlphaLisa technology, FRET) to study protein-protein, protein-DNA and protein-ligand interactions.
  • Fluorescence imaging: Use of conventional spinning-disk confocal microscopy and super-resolution microscopy to localize proteins and DNA and probe their dynamics in live or fixed cells (mammalian cells and bacteria).
    Technical facilities at IBS or on EPN Campus: M4D imaging platform; Biophysical and SPR/BLI platforms; High-throughput crystallization facility at EMBL; X-ray data collection at ESRF.

OU NOUS TROUVER ?

UMR 5075 Institut de Biologie Structurale (IBS)
71 avenue des Martyrs
38044 Grenoble
http://www.ibs.fr/research/research-groups/viral-infection-and-cancer-group-c-petosa/timmins-team/