Services and Pricing

ES Cell Microinjection

Another popular method of generating transgenic mice is by injecting Embryonic Stem (ES) cells into an embryo. This service enables investigators to generate chimeric mice from genetically modified mESCs and is an essential step in the generation of precisely modified alleles (conditional, knock-in, or null alleles). Only ES cells that have undergone homologous recombination and have been rigorously screened for the desired genotype are cultured and then injected into the cavity of a 3.5 day old embryo.

ES cells are microinjected into the blastocoele cavity of a 3.5 day old embryo derived from natural matings of C57Bl/6 mice. After the injected embryos have been transferred into the uterus of a pseudopregnant recipient animal, the animals become the financial responsibility of the investigator and are housed under his/her animal protocol number but will still be housed within the Barrier facility. Pups will be born about 3 weeks after injected blastocyst are transferred to a recipient animal. Once hair color has established, percentage of chimericism is noted.

Experimental Flow:

1. PI submits appropriate service form to TMESCSR for microinjection
2. Service forms are reviewed and approved by the Co-Directors of resource
3. Injections are scheduled, mice are ordered
4. Injections are performed, embryos are transferred to pseudopregnant females
5. Pups born 17 to 18 days post injection
6. Pups weaned and chimeric percentages are determined by Transgenic Core staff at 3 weeks of age
7. Non-chimeric littermates are serology tested at 6 weeks of age

8. >DAC staff review serology results, approve movement of mice, and transfer transgenic founders to PIs mouse housing room at 7 weeks of age