Chromosome transfer via cell fusion.

Intact chromosomes as well as chromosome fragments can be vehicled into various recipient cells without perturbing their ability to segregate as free elements; chromosome transfer can be performed both in cultured cells and in living animals. The method of choice to shuttle single chromosomes between cells is microcell fusion named microcell mediated chromosome transfer (MMCT). The use of MMCT is mandatory in a number of applications where alternative chromosome transfection procedures are ineffective; however, the main drawback is the extremely low efficiency of the technique. Recently, we developed a new procedure to shuttle an engineered human minichromosome from a Chinese hamster ovary hybrid cell line to a mouse embryonic stem cell line. This technology ultimately consists in micronucleated whole cell fusion (MWCF) without microcell isolation. Therefore, MWCF is much more simple than MMCT; moreover, chromosome transfer efficiency is higher. The main limit of the MWCF approach is that it can be employed only with parental cells of different species, while the MMCT protocol can be adapted to any donor and recipient cell line. This chapter will describe both the protocols that we currently use for MMCT and MWCF. The efficiency of the two protocols strictly depends on the parental cell lines to be used for cell fusion.