Differentiated somatic cells are more efficient than adult stem cells for cloning by somatic cell nuclear transfer. Mus musculus

Since the creation of Dolly, the first sheep cloned via somatic cell nuclear transfer (SCNT), in 1997, more than a dozen species of mammals have been cloned using this technology. One hypothesis for the limited success of cloning via SCNT (1-5%) is that the clones are likely derived from adult stem cells, which form an extremely small fraction in most adult tissues. Support for this hypothesis is that the cloning efficiency of full term development using embryonic stem (ES) cells as nuclear donors is 5-10 times higher than that for somatic cells as nuclear donors. Additionally, cloned pups could not be produced directly from cloned embryos derived from nuclei of differentiated B and T cells or neuronal cells. The question remains: can SCNT-derived animal clones be derived from truly differentiated somatic cells? We tested this hypothesis with mouse hematopoietic cells at different differentiation stages: hematopoietic stem cells (HSCs), progenitor cells (HPCs), and granulocytes. Surprisingly, we found that cloning efficiency increases over the differentiation hierarchy. The terminally differentiated post-mitotic granulocytes yielded the greatest cloning efficiency and we produced two cloned pups from granulocytes. We conclude that cloned mammals could be directly derived from post-mitotic differentiated somatic cells. Keywords: cell type comparison Overall design: single channel Affymetrix arrays to confirm cell-type specific gene expression profiles