Human pluripotent reprogramming with CRISPR activators

Abstract

CRISPR/Cas9 based gene activation (CRISPRa) is an attractive tool for cellular reprogramming applications due to its high multiplexing capacity and direct targeting of endogenous loci. Here we present the reprogramming of primary human skin fibroblasts into induced pluripotent stem cells (iPSC) using CRISPRa, targeting endogenous OCT4, SOX2, KLF4, MYC and LIN28A promoters. The basal reprogramming efficiency can be improved by an order of magnitude by additionally targeting a conserved Alu-motif, enriched near genes involved in embryo genome activation (EEA-motif). This effect is mediated in part by more efficient activation of NANOG and REX1. These data constitute a proof of principle that somatic cells can be reprogrammed into iPSC using only CRISPRa. Furthermore, the results unravel previously uncharacterized involvement of EEA-motif-associated mechanisms in cellular reprogramming.