A simple assay for optimizing yeast-mammalian cell fusion conditions.

Polyethylene glycol (PEG)-induced cell fusion can be a useful method for the transfer of yeast artificial chromosomes (YACs) from yeast spheroplasts to mammalian cells in culture, although success varies between recipient cell types. Experiments aimed at determining optimum fusion conditions can also be very time-consuming. To minimize this difficulty, a reporter plasmid has been constructed that allows yeast-mammalian cell fusion rates to be determined within 3 d. The speed and sensitivity of the assay should allow a more systematic evaluation of cell lines for their capacity to fuse with yeast, and for rapid optimization of fusion parameters.