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:
- JM8.A1 (Agouti B6N)
- JM8.A3 (Agouti B6N)
- JM8.N4 (B6N)
- VGB6 (B6N)
- R1 (129X1 X 129S1)*
- G4 (129S6 X B6Ncr)*
- E14TG2a (129P2/OlaHsd)*
- AB2.2 (129S5/SvEvBrd)*
- GS1 (129X1/SvJ)*
- W9.5 (129Sv)
*note that 129 substrains have complex genealogy and genetics; the major substrains have recently been given new nomenclature.
Frequently Asked Questions
- How are chimeric animals generated?
- Are all ES cell clones capable of generating chimeric mice?
- What is meant by ‘a highly chimeric mouse’?
- What does the coat color chimerism tell you about the animal? (What is the significance of coat color chimerism?)
- Are all chimeric mice capable of transmitting the mutation though the germline?
- What strain do I breed with my chimeras to generate heterozygous mutants?
- Mating schemes for 129-derived chimeras
- Mating schemes for B6-derived chimeras
- Do I have to continue using Southern Blot analysis to genotype the F1 pups?
- How do I go about mating my chimeric mice?
- Should I breed chimeric females?