Northwestern University Feinberg School of Medicine

Center for Genetic Medicine

ES Cell Injection

The TTML can culture and/or inject ES cells for investigators who have either generated targeted clones in their lab or obtained ES cell clones from another source. Investigator provided ES cells are injected into the cavity of an expanded blastocyst stage embryo and injected embryos are surgically transferred into the reproductive tract of recipient females.

A C57BL/6 mouse colony is routinely available for microinjection of 129- and agouti B6-derived ES cells. An albino population of B6(Cg)-Tyrc-2J/J is also maintained in a more limited capacity for investigators with C57BL/6-derived ES cell clones. Investigators with ES cell lines derived from other strains should contact the laboratory for additional information.

Not all ES cell clones will result in the production of chimeric mice (FAQ) and not all chimeric mice are capable of transmitting the mutated allele though the germline (FAQ). The ability to generate germline transmitting chimeras rests solely with the pluripotent capacity of the microinjected ES cells. Keeping ES cells in a non-differentiated state is largely a function of how carefully the cells are treated/handled during culture.

For these reasons, when working with ES cell clones cultured outside our lab, we cannot guarantee that microinjections will result in the generation of chimeric mice or that chimeric animals that are produced will be germline competent.

We have successfully generated germline competent chimeras from investigator-supplied targeted clones derived from the following parental ES cell lines:

*note that 129 substrains have complex genealogy and genetics; the major substrains have recently been given new nomenclature.

Frequently Asked Questions