EUCOMM

The EUCOMM program is funded by the European Union sixth R&D programme to make a library of mutant mouse embryonic stem cell clones (ES cells), to enable the mouse research community to rapidly create mutant mice with specific mutant genes. The EUCOMM consortium is a member of the International Knockout Mouse Consortium, (an organisation including the EUCOMM, KOMP, NorCOMM and TIGM consortia) which reflects a commitment to share and promote their products and technology with the international research community.^[2]

Each stem cell contains one mutant gene copy and one 'wild-type' (normal) gene copy. The entire library is intended to mutate 13,000 genes in total. Of these 13000 mutant genes, 8000 mutations in mouse ES Cells are 'targeted': that is, the mutation which knocks out gene function is inserted precisely into the genome. The remaining 5000 mutations are derived from 'gene-traps'. These mutations are created by infecting ES Cells with an appropriately modified retrovirus. The retrovirus inserts itself 'randomly' into the mouse genome. When it inserts into a gene's intron, the introduced DNA will stop that gene copy being expressed, and the gene is considered to be knocked out (see gene trapping).^[3][4]

The mutations introduced in the ES Cells are conditional: this means that the initial mutation can be modified - by the application of particular DNA-altering enzymes (site specific recombinases) to make the knockout initially latent in the genome. The gene can be later knocked out (inactivated) at a specific time-point or tissue-type in mutant mice derived from the mutant ES Cells, by appropriate breeding to other transgenic mice. This conditionality is a key property of the entire resource, and it allows a more nuanced study of the effects of the gene-knockout.