Overview

     The Mouse Gene Manipulation Core centralizes the production of genetically altered mice for IDDRC investigators in a cost-effective and efficient manner. The Core also provides expert assistance in the additional areas required for generating genetically altered mice, including transgene and targeting construct production, and transgenic mouse colony management. Core personnel are available to train investigators in all of the techniques required for the generation of genetically modified mice.

     The mouse genome can be manipulated to generate novel mouse lines with specifically targeted or random (“transgenic”) mutations. The Mouse Gene Manipulation Core centralizes the production of genetically altered mice for IDDRC investigators in a cost-effective and efficient manner. It also provides expert assistance in the additional areas required for generating genetically altered mice, including transgene and targeting construct production, and transgenic mouse colony management. Core personnel are available to train investigators in all of the techniques required for the generation of genetically modified mice.

 

Gene Targeting

            In the mouse, specific mutations can be “targeted” to a desired location in the genome. These mutations range from complete deletion of specific genes (”knock-outs”) down to single nucleotide base changes. Other mutations may swap one gene for another. In many cases, conditional targeting allows investigators to control the timing during development when a targeted mutation occurs and/or the specific tissues in which this mutation occurs.

             Gene targeting exploits the pluripotency of mouse embryonic stem (ES) cells which, when injected into host mouse embryos, are capable of generating germ cells (sperm and eggs) that can pass their genetic content on to subsequent generations. ES cells are manipulated in culture to alter endogenous ES cell genes with specific mutations. These “targeted” ES cells are then injected into mouse embryos that are grown to fully mature mice. ES cells contribute to the development of the germ cells, and the mating of these mice result in the passage of the targeted mutation to the next generation of mice.

Transgenics

            Transgenic mouse lines are those in which exogenous DNA (transgenes) are randomly integrated into the genome. Transgenes direct the expression of molecules that can disrupt normal development and disease processes. Transgenes consist of promoter sequences and coding sequences that direct the expression of proteins or RNA molecules that inhibit specific gene expression (RNAi). A variety of different promoter sequences allow researchers to limit the expression of transgenes to specific tissues and to specific times during development. Standard transgenic technology involves the microinjection of transgenic DNA sequences into the pronuclei of single-cell embryos. In a subset of the injected embryos, the injected DNA will stably insert into the mouse genome and be transmitted to subsequent generations upon breeding of the adult animals.