Transgenic and Knockout Core

Genetically engineered mice are powerful tools for studying the molecular genetic basis of human diseases. The purpose of the Mayo Clinic Transgenic and Knockout Core is to generate genetically altered mice for investigators at all three Mayo Clinic campuses.

The Transgenic and Knockout Core provides two main services: the generation of gene-targeted mice and the production of transgenic animals. The gene targeting service was established in 1999, while the transgenic service was established in 2006. These comprehensive services allow investigators with little or no prior experience in generating transgenic or knockout animals to introduce genetically altered mice into their research programs.

The Transgenic and Knockout Core designs and purifies transgenic DNA constructs and injects them into fertilized eggs. The core generates transgenic founders from these eggs and crosses the resulting mice to wild-type mice to transmit the transgene through the germline.

Additionally, the core designs gene-targeting vectors to generate classical or conditional knockout mice or hypomorphic alleles or to introduce point mutations in endogenous genes; electroporates the vectors into embryonic stem cells; and uses Southern blots to screen for clones carrying the desired alteration. Correctly targeted clones are karyotyped and injected into host blastocysts. Chimeric males are bred to wild-type females to establish germline transmission of the targeted mutation.

Success rates for transgenic and gene-targeting services are high — more than 90 percent.

The core also injects commercially available gene trap embryonic stem cell clones into blastocysts and Reed cells with resulting chimeras to establish germline transmission.