Description
Reprogramming somatic cells to induced pluripotency by Yamanaka factors is usually slow and inefficient, and is thought to be a stochastic process. We identified a privileged somatic cell state, from which acquisition of pluripotency could occur in a non-stochastic manner. Subsets of murine hematopoietic progenitors are privileged, whose progeny cells predominantly adopt the pluripotent fate with activation of endogenous Oct4 locus after 4-5 divisions in reprogramming conditions. Privileged cells display an ultrafast cell cycle of ~8 hours. In fibroblasts, a subpopulation cycling at a similar ultrafast speed is observed after 6 days of factor expression, and is increased by p53-knockdown. This ultrafast-cycling population accounts for >99% of the bulk reprogramming activity in wildtype or p53-knockdown fibroblasts. We compared the transcriptomes of the fast cycling cells with those of slower hematopoietic progenitors, bulk fibroblasts and established iPS cells. Overall design: 3-5 replicates for each of the six cell types were included: 4 replicates for established iPS cells, 4 replicates for bulk mouse embryonic fibroblasts (MEF), 4 replicates for fast cycling MEF, 4 replicates for slow cycling MEF, 5 replicates for fast cycling granulocyte monocyte progenitors (GMP) and 3 replicates for slow cycling GMP.