TGTF has successfully implemented CRISPR/Cas9 technology to generate gene targeted animal models for mice and rats by pronuclear microinjection and electroporation (upcoming). The advantages of CRISPR/Cas9 genome editing for the creation of unique mouse models include time-savings, potential reduction in animal usage, and overall cost effectiveness. The full services include molecular design, guide RNA validation, pronuclear microinjection or electroporation, embryo transfer to surrogate mothers, and care of newborn mice till weaning. Customers should be responsible for genotyping to confirm transgenic founders. The turnaround time is around 3-4 months. This service is now available for C57BL/6 strain which was previously very hard to be used for the gene targeting in mice.

This service is also available to meet some customers’ special needs for classical transgenesis by random insertion of a transgene. We guarantee 3 founder transgenic mice for a neutral construct, or injection of 200 zygotes of FVB/N or C57BL/6 strains. Customers should be responsible for genotyping to confirm transgenic founders.

Because of their plasticity, embryonic stem (ES) cells are traditionally employed for gene targeting in mice. Mouse ES cells are electroporated with a targeting vector for DNA integration. After colony screening, positive clones are expanded and then injected into a normal mouse blastocyst. The blastocysts colonized with the ES cells are transferred into surrogate mothers and developed into chimeric mice. These mice are then bred with mice to produce animals that have germline transmission of the targeted gene. The turnaround time is around 6-9 months. ES cells to be used in this service include those derived from 129 and C57BL/6 strains. Targeted ES cells from public bioresources or other researchers are also be used in this service.

Any GEM may potentially encounter multiple problems, such as infertility, genetic drift, and loss or acquisition of specific phenotypes, particularly when maintained over the years. To overcome these problems, Assisted Reproductive Techniques (ART) and Cryogenic Techniques (CT) have been employed in the facility.

The above-mentioned cryopreserved embryos and sperms can be used for the re-establishment of a particular mouse strain. This procedure is a rederivation by which the embryos are transferred into the reproductive tract of a pseudopregnant mouse in order to allow implantation, gestation, and birth.

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