Development and therapeutic application of transposon-based vectors

Abstract

Transposons are mobile genetic elements that move between or within vectors and chromosomes. For the transposition, an enzyme called transposase recognizes transposon-specific terminal inverted repeat sequences (IRs) located on both ends of transposons, and remove them from their original sites and, integrates them into other sites. Because of this feature, transposons containing genes of interest between their two IRs are able to carry the genes from vectors to chromosomes. Transposons are promising systems for chromosomal integration because they can not only integrate exogenous genes efficiently, but also be transfected to a variety of cells or organs using a range of transfection methods. In this review, we focused on the therapeutic application of transposons. A few transposons can integrate transgenes into mammalian chromosomes. They have been used in preclinical studies of gene therapy and cell therapy. In addition, they have recently been used for generation of induced pluripotent stem cells. Transposon-based integrative vector systems have two components. One is the transposon containing transgenes, and the other is the expression cassette of the transposase. Both viral and non-viral vectors have been used to deliver these two components to mammalian cells or organs, and sustained transgene expression has been achieved. Transposon-mediated sustained transgene expression has also produced therapeutic effect in disease models of hereditary and chronic diseases. Although transposon-based integrative vector systems have problems, such as insertional mutagenesis, studies to overcome these problems have been progressing, and these vector systems will become indispensable tools to cure refractory diseases. © 2009 The Pharmaceutical Society of Japan.