Tc8, a Tourist-like transposon in Caenorhabditis elegans

Members of the Tourist family of miniature inverted-repeat transposable ele ments (MITEs) are very abundant among a nide variety of plants, are frequen tly found associated with normal plant genes, and thus are thought to be im portant players in the organization and evolution of plant genomes. In Arab idopsis, the recent discovery of a Tourist member harboring a putative tran sposase has shed new light on the mobility and evolution of MITEs. Here, we analyze a family of Tourist transposons endogenous to the genome of the ne matode Caenorhabditis elegans (Bristol N2). One member of this large family is 7568 bp in length, harbors an ORF similar to the putative Tourist trans posase from Arabidopsis, and is related to the IS5 family of bacterial inse rtion sequences (IS). Using database searches, we found expressed sequence tags (ESTs) similar to the putative Tourist transposases in plants, insects , and vertebrates. Taken together, our data suggest that Tourist-like and I S5-like transposons form a superfamily of potentially active elements ubiqu itous to prokaryotic and eukaryotic genomes.