Tc1/mariner

The transposon consists of a transposase gene, flanked by two terminal inverted repeats (TIR).

Two short tandem site duplications (TSD) are present on both sides of the insert.

Transposition happens when two transposases recognize and bind to TIR sequences, join together and promote DNA double-strand cleavage.

The DNA-recognition domain has two paired box sequences that can bind to DNA and are related to various motifs found on some transcription factors; the two paired boxes are labeled PAI and RED, both having the helix-turn-helix motif common for DNA-binding domains.

The catalytic domain has the hallmark DDE (sometimes DDD) amino acids that are found in many transposase and recombinase enzymes.

[9] Experiments show that this element "jumps" in human cells, with its transposase as the only protein required.

[16][17] There are an estimated 14,000 copies of Mariner in the human genome comprising 2.6 million base pairs.

Although both types are inactive, one copy of Hsmar1 found in the SETMAR gene is under selection as it provides DNA-binding for the histone-modifying protein.

[22] The Himar1 element has been isolated from the horn fly, Haematobia irritans and can be used as a genetic tool in Escherichia coli.