Scientific Programmes
Biotechnology Programme
Transgenic Mice Core Unit
Overview Last update May/2010
In 2009 the Transgenic Unit generated 26 new gene targeted mouse lines (including knockout, knockin and conditional models). It also obtained 19 founders corresponding to 6 different transgenic constructs or BACs microinjected into mouse zygotes. In addition 48 new mouse lines have been introduced into the CNIO Animal Facility by rederivation and 102 lines have been frozen by sperm (92 lines) or embryo (10 lines) cryopreservation.
In collaboration with E. Wagner’s Group (Genes, Development and Disease) the Unit has incorporated the generation of targeted conditional transgenic mice using KH2 ES cells. This is a highly efficient, well-controlled and reproducible system for conditional transgenic mice generation. Firstly, it overcomes the problem of random integration and positional effects frequently found in conventional transgenic mice, since all transgenes are integrated as a single copy into the same highly permissive locus for transgene expression. The system (Figure) allows for targeted integration of the tetOp-GOI-pA element into the Collagen1a1 locus by Flp-mediated recombination. It requires previous cloning of the cDNA of interest (GOI) into the pBS31-rgbpA-plasmid. Moreover, KH2 ES cells also carry the rtTA transactivator targeted into the Rosa26 locus which permits: 1) in vitro confirmation of transgene expression and 2) in vitro studies in ES cells. Both alleles, Rosa26-rtTA and Cola1-tetOp-GOI-pA, can be segregated after chimera-germ line-transmission. As a consequence, tissue-specific tet-conditional transgenic mice can easily be achieved by crossing mice carrying only the Col1a1-tetOp-GOI-pA knockin allele with any tissue-specific tTA/rtTA expressing mouse line.
In collaboration with both M. Blasco’s Telomeres and Telomerase Group and M. Serrano’s Tumour Suppression Group, our Unit has been involved in the generation and characterisation of iPS cells obtained from fi broblasts and keratynocytes derived from p53-/- and Ink4a-/- mice as well as various generations of telomerase deficient mice. This work has contributed to the understanding of the functions of these genes in the reprogramming process induced by expression of the transcription factors Sox2, Oct3/4 and Klf4.
The Unit has also developed new mouse models to study the lymphatic system and lymphangiogenesis in mice and their relation to tumour development and spread. These models will help to elucidate the molecular mechanisms of lymphatic development and maturation as well as the contribution of different pathways to tumour expansion through the lymphatic system – a process associated with a bad tumour prognosis in the clinical setting.
