Centre de Ressources Biologiques Xénopes (CRB)

The Centre de Ressources Biologiques (CRB) Xénope (Xenopus Biological Resource Center), established in 2003, is one of only two platforms in Europe to associate research and development to a national husbandry center dedicated to xenopus.

In basic research, xenopus is used for studies in development biology, cell biology, molecular genetic and in the area of ecotoxicology. The oocyte, enabling the expression of many heterologous proteins, is a true sample tube to study channels, receptors and transporters. It is also used for the functional screening of molecules showing therapeutic potential. The adaptation of xenopus model to new technologies such as customized nucleases and  automated screening tools, enables a wider use of the amphibian model.


The Xenopus Biological Resource Center, thanks to its animal facility with a capacity of  7000 amphibians, is home to two species :

  • Xenopus laevis (6000) is a South African toad, selected for its ease of breeding as well as for the big size of its oocytes. Embryos produced in large quantities are developing rapidly at ambient temperature.
  • Xenopus tropicalis (1000) is harder to breed, but offers the advantage of a shorter life cycle and a diploid genome.

The Xenopus Biological Resource Center certified IS0 9001 since 2007, has got the double certification NF X50-900 & ISO 9001:2015.

The CRB  Xénopes (Xenopus Biological Resource Center) fulfils a dual mission regarding the national scientific community either in the public or private sector. These missions concern researchers wishing to use regularly or occasionally this amphibian model in their experiments.

Breeding and distribution of animals and biological material

  • To ensure the production and the distribution of animals and embryos
  • To ensure the production and the distribution of related biological material (DNA, RNA, tissues, ...)
  • To ensure the supply of oocytes (in relation with Biopredic International)

Management of projects

  • To ensure R&D activity for the best use of Xenopus model potentialities.
  • To create transgenic lines expressing a protein of interest or for the functional study of regulatory regions by using a fluorescent protein (eGFP for example) as an in vivo reporter gene.
  • To produce oocytes expressing proteins of interest
  • To perform oocyte screening for measurement of transmembrane currents (electrophysiological screening automate, Hiclamp system)
  • To meet any demand for researchers wishing to use the Xenopus model, by carrying out the required experiments, by trainings or by hosting researchers and technicians

Specific trainings dedicated to aquatic species

  • Regulatory training for people developing experimental procedures on "aquatic species"
    A 57-hour CNRS course (45 hours training courses + 12 hours practical work) for research scientists and engineers managing a direct scientific authority in experimentation on animals. This training course includes the program for staff participating to experimentation on animals, such as technicians. Training in collaboration with three partner centers of CELPHEDIA: AMAGEN, CRB Xenopus and CE2F-PRIM.
    Training content specific to aquatic species:
    ① Regulation in the use of animals on scientific purposes
    ② Transportation of aquatic animals
    ③ Ethics: review of ethics procedures, ethics committees, the 3R rule, pain scale and assessment of severity, animal welfare and stress, analgesia, pain and nociception, euthanasia
    ④ Which animal for what model? Aquatic models. 
    ⑤ Handling of animals, anaesthesia process, pre- and postoperative care 
    ‹⑥ Zoology, comparative anatomy, general physiology, ethology, reproduction
    ⑦ Management of environmental parameters, management of an aquatic animal facility
    ⑧ Infectious diseases and health status, diseases of aquatic animals bred in captivity
    Trainings exclusively limited to CNRS employees or employees working in a CNRS unit: 7 days
    ▪ 2 sessions in Marseille in 2018: April 5-13, September 13-21
  • Trainings on request for the use of xenopus model (transgenesis, expression in oocytes...).

Courses at the university

  • Master in biology-biotechnology and therapeutic research at the University of Nantes
  • Master in genomic surgery at the University of Rennes

The CRB  Xénopes (Xenopus Biological Resource Center) wants to develop a semiautomatic microinjection platform with two major objectives:

  • High throughput injection of poly(A)+ RNAs into Xenopus oocytes (in collaboration with Biopredic International) to obtain cells expressing molecules characteristic of certain cell types on their surface .
  • Implementation of an automated electrophysiology platform to increase the electrophysiological analysis capabilities for the study of interactions between membrane proteins and their (s) ligand (s) through the development of a dedicated platform.

Study of transmembrane receptors through screening of oocytes

High throughput electrophysiological screening of Xenopus oocytes expressing exogenous genes in the frame of pharmacological or agricultural projects.

Four studies in progress :

  • Olfactory receptors of a crop pest butterfly, to identify natural odorous ligands, agonists or antagonists to orphan olfactory receptors (ORs) pests.
  • Acetylcholine receptor, which is the target of drugs (nicotine, ethanol) and current therapeutics (anaesthetics, anxiolytics, anti-smoking and anti-Alzheimer's). The project aims to discover new agonist, antagonist and allosteric modulators of these receptors mostly orphans.
  • Ligand receptor of dentritic cells.
  • Development of a test that detects toxins of cyanobacteria.

Genetic engineering

  • Development of transgenesis / mutagenesis technologies (Tale Nuclease, CRISPR/Cas9) in partnership with the National Infrastructure TEFOR
  • Generation of animals deficient in desmin (structuring protein of muscle fibers involved in human muscular dystrophies) using TALE nucleases.

CRB logoRennes

CRB logoXenopus laevis and Xenopus tropicalis

CRB logohttp://xenopus.univ-rennes1.fr/

CRB logo