How are ES cells made into a mouse?
Mouse ES cells are electroporated with the gene-target or gene-trap vectors and the resultant genetically modified ES cell line is then stored in an ES cell library. Once these ES cell lines have been established, they can be microinjected into mouse blastocysts and implanted into pseudopregnant female mice. The pups generated are assessed for the degree of chimerism and high percentage chimeric animals are crossed with wild type mice to obtain germline transmission of the mutant allele. The resulting heterozygotes are shipped to the researcher for breeding to homozygosity and characterisation.
