Efficient generation of germ line transmitting chimeras from C57BL/6N ES cells by aggregation with outbred host embryos

Abstract

Genetically modified mouse strains derived from embryonic stem (ES) cells have become essential tools for functional genomics and biomedical research. Large scale mutagenesis projects are producing libraries of mutant C57BL/6 (B6) ES cells to enable the functional annotation of every gene of the mouse genome. To realize the utility of these resources, efficient and accessible methods of generating mutant mice from these ES cells are necessary. Here, we describe a combination of ICR morula aggregation and a chemically-defined culture medium with widely available and accessible components for the high efficiency generation of germline transmitting chimeras from C57BL/6N ES cells. Together these methods will ease the access of the broader biomedical research community to the publicly available B6 ES cell resources.

Figure 1. Representation of fertility and germline transmission status of chimeric mice derived from C57BL/6NTac-C2 targeted clones based on degree of coat colour chimerism.

A. Percentage of mice derived from the same ES cell lines in the same experiments cultured in KOSR+2i or VGB6 prior to aggregation and tested for germline transmission of the ES cell genome. B. Number of mice in each category from A.