Gene therapy supplies your cells with genes either to replace faulty ones, or to supply genes that can combat other forms of disease. These genes are then translated into proteins. Often, however, a number of different proteins (and hence genes) are required for successful therapy. This work is designed to develop a system whereby multiple genes can be strung together to form a single gene: a multi-gene. It is much easier and safer to introduce one gene via gene therapy, than try to introduce many individual genes into a cell. The chances of this new type of multi-gene being able to produce all of its different proteins (and all at the same time) is very much higher than is the case with many individual genes. The methods we wish to develop here will extend the range of diseases that may be treated by gene therapy.