title: Nuclear reprogramming in heterokaryons is rapid, extensive, and bidirectional.
abstract: An understanding of nuclear reprogramming is fundamental to the use of cells in regenerative medicine. Due to technological obstacles, the time course and extent of reprogramming of cells following fusion has not been assessed to date. Here, we show that hundreds of genes are activated or repressed within hours of fusion of human keratinocytes and mouse muscle cells in heterokaryons, and extensive changes are observed within 4 days. This study was made possible by the development of a broadly applicable approach, species-specific transcriptome amplification (SSTA), which enables global resolution of transcripts derived from the nuclei of two species, even when the proportions of species-specific transcripts are highly skewed. Remarkably, either phenotype can be dominant; an excess of primary keratinocytes leads to activation of the keratinocyte program in muscle cells and the converse is true when muscle cells are in excess. We conclude that nuclear reprogramming in heterokaryons is rapid, extensive, bidirectional, and dictated by the balance of regulators contributed by the cell types.
authors.affiliation: Department of Microbiology and Immunology and Stem Cell Institute, Stanford University School of Medicine, 269 Campus Dr., Stanford, CA 94305-5175, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Palermo
authors.forename: Regis
authors.initials: R
authors.lastname: Doyonnas
authors.forename: Nidhi
authors.initials: N
authors.lastname: Bhutani
authors.forename: Jason
authors.initials: J
authors.lastname: Pomerantz
authors.forename: Ozan
authors.initials: O
authors.lastname: Alkan
authors.forename: Helen M
authors.initials: HM
authors.lastname: Blau
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002459:Cell Fusion; D065150:Cellular Reprogramming; D020869:Gene Expression Profiling / Q000379:methods*; D006801:Humans; D006822:Hybrid Cells / Q000378:metabolism / Q000502:physiology*; D015603:Keratinocytes / Q000502:physiology; D051379:Mice; D020411:Oligonucleotide Array Sequence Analysis