Transgenic Mice

In the Precision Mouse Engineering Core, transgenic mice are generated by pronuclear microinjection of foreign DNA fragments into one-cell-stage mouse embryos. On average, it takes about 3-4 months to generate a transgenic mouse strain.

The Precision Mouse Engineering Core can help investigators design transgenic DNA constructs. Once a transgenic construct has been assembled, the investigator files a request for microinjection services.

Core personnel then excise the transgene from the plasmid backbone and prepare it for microinjection. They also set up superovulation and matings to obtain one-cell-stage embryos for microinjection and prepare pseudopregnant surrogate mothers for embryo-transfer procedures.

The DNA construct is typically injected into fertilized eggs over a period of two days. Microinjected embryos are transferred into surrogate mothers, which develop these embryos to term.

Once pups are born from these eggs, tail biopsies are collected to prepare genomic DNA. This DNA is screened by polymerase chain reaction analysis for the presence of transgenic DNA. Then transgenic animals are bred to establish a cohort of mice that can be used to study the phenotypic consequences of transgene expression.