The tools used in this novel method are artificially designed zinc-finger nucleases (ZFNs), synthetic proteins which are able to cleave DNA at a specifically determined site. Together with a gene targeting vector that contains the mutations under investigation, the ZFNs are injected directly into the murine one-cell embryos. The endogenous repair system induces the desired gene fragment into the mouse DNA with an achievement rate of 1.7 to 4.5 percent without prior selection. Using this method, the researchers have succeeded in breeding vital mice in which targeted specific genes have been replaced.
Now the researchers are seeking to improve the effectiveness of the method and are investigating the applicability of the method to other organisms. Scientists could thus use other model systems besides the mouse model. The new method also offers promising therapeutic approaches. "In the long run," Professor Wurst sais, "it is conceivable that not only new genes can be inserted using this method, but also that defective genes can be replaced with healthy ones."
This work was financially supported by the European Union within the European Conditional Mouse Mutagenesis Program and by the German Ministry of Education and Research within the DIGTOP project of the NGFN-Plus program.
Melanie Meyer, Martin Hrabe de Angelis, Wolfgang Wurst und Ralf Kuhn: Gene targeting by homologous recombination in mouse zygotes mediated by zinc-finger nucleases. Proceedings of the National Academy of Sciences; Early Edition, 04.08.2010 – DOI: 10.1073/pnas.1009424107
Source: Technical University