Manipulation of human minichromosomes to carry greater than megabase-sized chromosome inserts

For introducing regions of human chromosomes greater than a megabase into cells or animals, we have developed a chromosome-cloning system in which defined regions of human chromosomes can be cloned into a stable human minichromosome vector in homologous recombination-proficient chicken DT40 cells. The stable minichromosome vector allowed a 10 Mb-sized region of the mitotically unstable human chromosome 22 to be stably maintained in mouse embryonic stem (ES) cells, and in mice. Furthermore, we demonstrated functional expression of human genes from the HAC in mice. This study describes a stable cloning and expression system for greater than megabase-sized regions of human chromosomes.