Use of somatic cell fusion to reprogram globin genes.

The developmental phenomenon of hemoglobin switching occurs in all classes of vertebrates and is due to differential regulation of divergent globin genes which are arranged in chromosomally clustered families. By fusing erythroid cells of different developmental programs, it has been shown that erythroid nuclei of either early or late developmental stage can be reprogrammed, i.e. the gene switch can be reversed in adult erythroid nuclei and/or prematurely-induced in fetal/embryonic erythroid nuclei. Experiments with heterokaryons demonstrate that the reprogramming is due to trans-acting factors that are developmental-stage-specific. These results suggest the feasibility of using fusisome-carried sets of nuclear factors to reprogram somatic cells.