The isolation of heterokaryons and hybrids by a selective system using irreversible biochemical inhibitors

A general method for isolating heterokaryons between any type of cells was developed using irreversible biochemical inhibitors. Cells were treated with a lethal dose of a reagent, washed free of unreacted inhibitor, and then fused to cells treated in a similar fashion with an agent of different specificity. Unfused parental cells or homokaryons do not have their damaged molecules replaced and thus die. Only heterokaryons receive a full complement of those molecules necessary for cell survival. Heterokaryons formed by this technique are viable, divide, and give rise to hybrid populations. Although more efficient inhibitors may be found, iodoacetamide and diethylpyrocarbonate provide a workable combination that demonstrates the feasibility of the approach. Since cells with heritable selective markers are not required, this technique should greatly expand the range of cell types suitable for hybridization experiments. In addition, it permits studies on pure populations of heterokaryons before any cell division has occurred.