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Blastocyst Injection (of Standard ES Cells from 129 or 129/B6 strains)

The ability of mouse pre-implantation embryos to incorporate cells from other embryos is fundamental to creating mutant mice. Thus when embryonic stem (ES) cells that have been genetically altered are microinjected into mouse E3.5 day embryos, mutant chimeras can be obtained. Since ES cells are pluripotent and can contribute to all cell types of an animal, including gametes, genetic alterations introduced into the ES cell genome can be propogated in the next generation to form a stable mutant mouse line.

GEMF Service

Genetically modified ES cells will be injected into C57Bl/6 or C57Bl/6 albino blastocysts. Injected blasts will then be transferred back to the uteri of foster females. Approximately three weeks after pups are born, facility personnel will inform investigators of the number of chimeras produced and their percentage chimerism. Chimeras selected by the investigator will then be transferred to the PI's animal protocol and animal colony.


$1600/cell line for MD Anderson investigators; $5120/cell line for external investigators

Time Line for Blastocyst Injection

  • Day 1: Microinject ES cell clone
  • Day 17: Pups born
  • Day 31: Investigator notified about births, male/female numbers, number of chimeras and % of chimerism. Investigator is responsible for turning in an animal order form for these mice to Veterinary Medicine at this time
  • Day 38: Wean chimeras and transfer to investigator (upon receipt of signed order from Veterinary Medicine)

To Obtain Service from the GEMF

  • Obtain authorization for animal research from the Office of Research Administration (animal protocol coordinator at Ext. 2-3220). The facility cannot initiate any experiment without an authorized animal research protocol number
  • Schedule an appointment with Jan Parker-Thornburg (713-745-2654 or e-mail to set an injection date 
  • Log in to, register for an account, then go to the site to request service

Chimeras will be transferred to the investigator upon weaning for subsequent breeding. Investigators must obtain and complete an animal order form with Veterinary Medicine for animal orders.

Read the Policies and Procedures section for important information regarding services rendered by the GEMF.

Note: The likelihood of a targeted ES cell clone contributing to the germ-line is highly dependent on the quality of the ES cells injected into the blastocyst. It is therefore essential that ES cells for injection are maintained under optimal conditions and in an undifferentiated state throughout their culture. We maintain the right to refuse injection of cells that are differentiated, or which show aberrant characteristics.

© 2015 The University of Texas MD Anderson Cancer Center