Unit: Mouse Genetics Engineering Center (Platform)
Director: Francina Langa Vives
The Centre d'Ingénierie Génétique Murine (CIGM) is a technological core facility created in 2003 at Pasteur Institute. This core facility aims to generate genetically-engineered mice either by classical transgenesis techniques or by homologous recombination in embryonic stem (ES) cells. The CIGM is open to the Pasteur community and also to external customers interested in new transgenic, knock-out or knock-in murine models.
The Centre d'Ingénierie Génétique Murine (CIGM), attached to the Département de Biologie du Développement, has been created in 2003. The CIGM is a novel technological core facility within the Institut Pasteur, which aims to generate new models of genetically-engineered mice by classical transgenesis techniques or by homologous recombination in embryonic stem (ES) cells (targeted transgenesis).
The classical transgenesis activity, which consists in the microinjection of the gene of interest into the pronuclei of fertilized eggs, was originally the main CIGM activity, and this activity has been developed in 2004 and 2005. The microinjected transgenes can include now DNA fragments, BACs and YACs. The genetic backgrounds proposed include hybrid ones like B6SJLF1 or B6CBAF1 together with pure genetic backgrounds like C57BL/6 or FVB. Classical transgenesis activity has been increased in 2005, specially concerning BAC microinjections and the use of C57BL/6 genetic background, which is particularly interesting in the field of neuroscience and immunology. Moreover, in 2005 we have started in the CIGM the technique of transgenesis by lentiviral constructs in order to increase the possibilities for transgene insertion in the mouse genome. The subzonal injection of viral particles containing the transgene of interest proved to be very efficient. Our results have effectively confirmed that almost the totality of pups (99%) obtained by this technique were positive for the transgene.
The homologous recombination technique in ES cells and subsequent microinjection of modified ES cells in mouse blastocysts allow the generation of germ line chimeras for targeted transgenesis in the endogenous gene. We have obtained our first germ-line chimeras in June 2004, and since then, several new heterozygous/homozygous mice corresponding to new knock-out or knock-in models have been created. In 2005, we have started the microinjection of modified ES cells from foreign laboratories. Thus, we have obtained germ-line chimeras after microinjection of gene trap AB1 ES cell clones coming from Sanger Institute (UK).
Since November 2005, the CIGM disposes of a new independent animal room including a surgery room in Fernbach building where the laboratory rooms of CIGM are also installed. This movement has improved the accessibility of the CIGM members from the laboratories to the animal facility, and most importantly, has increased by 45% the mouse housing capacity, which is essential in reason of the increase in the number of mouse lines created at CIGM. Moreover, the acquisition of ventilated racks have improved the quality of the health status of the mice generated at CIGM, which are dispatched to all the animal houses in Pasteur Institute and also external ones.
The benefits of the CIGM to Pasteur Institute and the national and international scientific communities are reflected in the list of collaborations since its creation in 2003. The CIGM interacts with an expanding list of Units in Pasteur Institute (belonging to 6 different Departments), and other Research Institutions in France (CNRS Unit UMR146-Institut Curie-Orsay, INSERM Units E9935-Paris, and U522-Rennes, the Institut National de la Transfusion Sanguine-Paris) and also in foreign countries (Université Libre de Bruxelles- Belgium, Universitat de Barcelona-Spain).
Interestingly, our core facility also provides expertise regarding the design of gene constructions suitable for transgenesis and homologous recombination experiments.
Keywords: mouse, transgenesis, homologous recombination, Embryonic Stem (ES) cells, microinjection