Mos1-mediated insertional mutagenesis in Caenorhabditis elegans.

We describe a protocol for mutating genes in the nematode Caenorhabditis elegans using the Mos1 transposon of Drosophila mauritiana. Mutated genes containing a Mos1 insertion are molecularly tagged by this heterologous transposable element. Mos1 insertions can therefore be identified in as little as 3 weeks using only basic molecular biology techniques. Mutagenic efficiency of Mos1 is tenfold lower than classical chemical mutagens. However, the ease and speed with which mutagenic insertions can be mapped compares favorably with the vast amount of work involved in classical genetic mapping. Therefore, Mos1 could be the tool of choice when screening procedures are efficient. In addition, Mos1 mutagenesis can greatly simplify the mapping of mutations that exhibit low penetrance, subtle or synthetic phenotypes. The recent development of targeted engineering of C. elegans loci carrying Mos1 insertions further increases the attractiveness of Mos1-mediated mutagenesis.