Members of the pogo superfamily of DNA mediated transposons in the human genome

A new superfamily of transposons from fungi, nematodes, and flies related to the pogo element of Drosophila Melanogaster was recognized that represents a branch of the extended superfamily of transposase and integrase proteins sharing a common D,D35E catalytic domain. Searches of human sequences in the public databases for similarity to this domain revealed at least two members of this new superfamily, with many highly mutated copies, in the human genome. A full-length consensus was constructed for one of them, which includes the MER37 medium reiteration frequency sequence recognized previously, from 343 human sequence accessions (261 of which are unique). Most of these were Expressed Sequence Tags, some were Sequence-Tagged Sites, and a few are from long genomic sequences. The 2417 bp consensus has the hallmarks of a pogo superfamily transposon, including 12 bp inverted terminal repeats, and encodes two long open reading frames. The first ORF encodes a polypeptide with 42% amino acid sequence identity to pogo in the D,D35E region. The second element shows 49% amino acid sequence identity with the first, and 40% with pogo in this region. These elements coincide with those described recently as Tigger1 and Tigger2, respectively. These transposons appear to have been active 80-90 Myr ago in the genome of an early primate or primate ancestor.