Cell fusion-induced reprogramming.

Genomic reprogramming can be accomplished by five different types of methods: nuclear transfer, cell fusion, in vitro culture, introduction of egg extract, and transduction of transcription factors. We have shown that fusion-induced reprogramming is an efficient method for reprogramming differentiated somatic cells to a pluripotential state (pluripotential reprogramming)--Oct4 gene reactivation occurs within 1-2 days postfusion of somatic cells with pluripotent stem cells. Reactivation of Oct4 can be monitored by detection of the GFP signal from the Oct4-GFP transgene of somatic cells. In the current report, we fused double transgenic (OG2/ROSA26) somatic cells with pluripotent embryonic stem (ES) cells, and demonstrated the presence of the somatic cell genome in all GFP-positive ES-like colony-forming cells, confirming their identity as the cell fusion hybrids.