International Mammalian Genome Society

The 15th International Mouse Genome Conference (2001)

Table of Contents * Complex Genetics * Developmental Genetics * Gene Annotation * Gene Discovery * Genome Sequencing * Functional Genomics * Mutagenesis * Presentations * Verne Chapman Memorial Lecture

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POSTER 237 - NEW ES CELL LINES FOR THE RAPID GENERATION OF INDUCIBLE KNOCKOUT MICE

Dr. Frieder Schwenk
Artemis  Pharmaceuticals GmbH
Neurather Ring 1
Cologne
51063
Germany

Co-Authors: 1)Seibler S, 1)Küter-Luks B, 1)Heimann C, 2)Eggan K, 1)Hennek T, 1)Kern H, 1)Zevnik B, 2)Jaenisch R, 1)Kühn R
Institutions: 1) ARTEMIS Pharmaceuticals GmbH, 2) Whitehead Institute for Biomedical Research and Department of Biology, Institute of Technology

Inducible, Cre/lox mediated gene targeting is a powerful tool to analyze gene function in adult mice. Furthermore, it permits to investigate the effect of induced gene inactivation in animal disease models. This aspect is of particular interest in the validation of genes for pharmaceutical drug development, as it provides an ideal model for the action of antagonistic drugs. However, the generation of conditional mouse mutants using the current technology is time consuming as several breeding steps are required. This problem can be addressed using the recent discovery that completely ES cell derived mice can be efficiently produced by the injection of hybrid ES cells into tetraploid blastocysts.

We have generated improved fusion proteins consisting of Cre and the ligand binding domain of the human estrogen receptor. Such fusion proteins are inducible by the administration of synthetic ligands. To derive a system that allows the rapid production of inducible mouse mutants, we inserted these constructs into the Rosa26 locus through homologous recombination in hybrid ES cells. To assay the activity of the CreER fusion proteins in vitro, we introduced a Cre-LacZ reporter into the second Rosa26 allele. We demonstrate that highly efficient recombination can be achieved within 72 h of induction, whereas no background recombination can be detected in the absence of drug. We are currently generating ES cell derived mice to study the potential of our system in vivo