DNA-based transposon system for the introduction of nucleic acid into DNA of a cell

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to novel tranposases and the transposon that are used to introduce nucleic acid sequences into the DNA of a cell.
A transposase is an enzyme that is capable of binding to DNA at regions of DNA termed inverted repeats.
Transposons typically contain at least one, and preferably two, inverted repeats that flank an intervening nucleic acid sequence.
The transposase binds to recognition sites in the inverted repeats and catalyzes the incorporation of the transposon into DNA.
Inverted repeats of an SB transposon can include two direct repeats and include at least one direct repeat.
Transposons are mobile, in that they can move from one position on DNA to a second position on DNA in the presence of a transposase.
There are two fundamental components of any mobile cut-and-paste type transposon system, a source of an active transposase and the DNA sequences that are recognized and mobilized by the transposase.
Mobilization of the DNA sequences permits the intervening nucleic acid between the recognized DNA sequences to also be mobilized.
DNA-transposons, including members of the Tc1/mariner superfamily, are ancient residents of vertebrate genomes (Radice et al.
, 1994; Smit and Riggs, 1996 Proc.
Natl.
Acad.
Sci.
USA 93, 1443-1448).
However, neither autonomous copies of this class of transposon nor a single case of a spontaneous mutation caused by a TcE insertion have been proven in vertebrate animals.
This is in contrast to retroposons whose phylogenetic histories of mutating genes in vertebrates is documented (Izsvak et al.
, 1997).
Failure to isolate active DNA-transposons from vertebrates has greatly hindered ambitions to develop these elements as vectors for germline transformation and insertional mutagenesis.
However, the apparent capability of salmonid TcEs for horizontal transmission between two teleost orders (Ivics et al.
, 1996) suggested that this particular subfamily of fish transposons might be transferred through even larger evolutionary distances