DISRUPTION AND SEQUENCE IDENTIFICATION OF 2,000 GENES IN MOUSE EMBRYONIC STEM-CELLS

The dramatic increase in sequence information in the form of expressed sequence tags (ESTs)(1) and genomic sequence has created a 'gene func tion gap', with the identification of new genes far outpacing the rate at which their function can be identified. The ability to create muta tions in embryonic stem (ES) cells on a large scale by tagged random m utagenesis provides a powerful approach for determining gene function in a mammalian system; this approach is well established in lower orga nisms(2,3). Here we describe a high-throughput mutagenesis method base d on gene trapping that allows the automated identification of sequenc e tags from the mutated genes, This method traps and mutates genes reg ardless of their expression status in ES cells, To facilitate the stud y of gene function on a large scale, we are using these techniques to create a library of ES cells called Omnibank, from which sequence-tagg ed mutations in 2,000 genes are described.