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GENE-10. A SIMPLE AND EFFICIENT METHOD FOR GENERATING MULTI-ALLELIC INSERTION-DELETION MUTATIONS AND PRECISE DELETIONS IN PRIMARY HUMAN CELL CULTURES


 CRISPR-Cas9-based technologies have revolutionized experimental manipulation of the human genome by enabling generation of site-specific genetic alterations, such as insertion-deletion (indel) mutations. None-the-less, limitations of the delivery and efficacy of these technologies restrict their application in primary human cells. Here, we present a simple and effective method for fast and penetrant induction of multi-allelic indels and near-precise deletions (ranging from ~50bp to >50kbp) in primary human neural stem/progenitor cell (NPC) and brain tumor-derived stem-like cell cultures using the CRISPR-Cas9 system. We report that mono-, bi-, or multi-allelic (depending on ploidy) indel efficiencies of >90% can be routinely achieved within 3 days, without the need for pre-engineering cells to express Cas9 or isolating clones. As a result, this method enables the quick generation of a series of knockouts at different genomic loci, which we illustrate by successively targeting TP53, CDKN2A, PTEN, and NF1 in human NPC populations, where ³95% loss of protein expression is observed. RNA-seq analysis of these NPC knockout pools confirmed gene expression changes including p53 transcriptional and Rb-axis targets, as well as NF1-dependent repression of major histocompatibility complex class II gene expression. Given its simplicity, this method is readily adaptable to other primary mammalian cell types.