The technology to create artificial chromosomes for mammalian cells now exists and their possible uses lave attracted press and commercial attention as vectors for large scale genetic manipulation -therapeutic or Biotechnological in intent. This attention has ignored the fact that these systems are currently rudimentary in their ::components and are based on a limited knowledge of the biology involved and of the optimal components required. This proposal aims to develop from the first generation systems available to us and to provide improvements to the components of artificial chromosome vectors which will make it possible to begin to use them as delivery vehicles.

We will do this by improving our knowledge and resources in the areas of centromeres, both in man and Mouse, telomeres, replication origins and large tester genes for the systems using a virally based system as a baseline. We will develop the necessary systems for delivery of large DNA molecules to a range of cells and will test the feasibility of germ line transmission of improved and existing versions of these constructs in mice. The program will initiate with seven specialist laboratories in the areas of telomeres, centromeres, replication origins, viral episomal vectors and DNA delivery focusing on the areas of their own expertise relevant to the project to develop components and expertise's necessary to achieve the above aims. In addition the basic biology of these components will be studied to provide a rational basis for developments. These components will then be tested 5ingly and in combination using established methods. This will involve exchange of materials expertise and Personnel. We will make progress towards artificial chromosomes which are more controlled in their construction; have defined sizes and capacities for gene expression and we will introduce them into a wide range of cell types and into mouse as a model organism.