Technological leap for the creation of mutant mice
March 7, 2017
- The Mouse Clinical Institute (MCI) is a founding member of PHENOMIN, the national infrastructure for the generation and analysis of murine models. By adapting CRISPR / Cas9 technology, researchers of PHENOMIN and the IGBMC have been able to quickly and efficiently generate mouse models of diseases related to variations in the number of copies of certain regions of the genome. These results are published on March 7 in Scientific reports.
The CRISPR / Cas9 "revolution"
Discovered in 2012, the technique known as "CRISPR / Cas9" allows to target DNA very precisely through a guide RNA. The latter is associated with an enzyme, Cas9, which makes it possible to cut, replace, inactivate or modify the targeted gene. More precise, faster and cheaper than all the techniques used to date, this method is now used in many laboratories to modify cells in vitro. Numerous studies have shown that its application in vivo is possible but the effectiveness of the methods remains limited in these cases.
Easily create mouse and rat models
To date, to create murine models, researchers use methods combining the Cre-Lox recombination system and the use of embryonic stem cells, but these processes are long and tedious, and it takes about 3-4 years to create a new mouse model. Here, scientists have adapted the CRISPR / Cas9 technique for the creation of mutant animals. They have doubled the RNA-guides, using two very similar guides to increase the efficiency of the break and have thus managed to modify important regions of the DNA (up to 24.4 Mb). Deletion, duplication, inversion, many configurations have been tested and validated by the generation of mouse lines carrying these mutations, and their transmission to the lineage. "The size of the targeted DNA section is not really a limiting factor, it's more the question of viability due to the removing certain genes that limits us" explains Marie-Christine Birling. Conclusion: it is now simple and fast (6-7 months) to create new disease models, good news for translational research.
Mouse and rat models of trisomy 21
With this new method developed at the ICS, Yann Hérault and his team at IGBMC have created new mouse models of trisomy 21, a disease due to the presence of an additional copy of the chromosome 21.
This was not possible with the previous techniques, but the researchers also succeeded in performing the same manipulations in the rat, thus creating an interesting model for evaluating behavior, knowledge, memory and social interactions. According to them this technique is adaptable to any species and its use could be made on human cells.
This study has been financed by the ANR, the Fondation Jérôme Lejeune and the Fondation Bettencourt-Schueller.