More recently, CRISPR/Cas9-mediated gene knockout has emerged as a powerful method to interrogate gene function (Wright et al., 2016), and inducible manipulation of gene expression in hPSCs using this approach has been reported (Chen et al., 2015; González et al., 2014; Mandegar et al., 2016). However, these methods are either very complex and time consuming, as they involve multiple genome editing steps that need to be individually tailored for each gene to be examined (Chen et al., 2015), or are not widely applicable in multiple differentiated cell types as they rely on inducible promoters that are not stably and homogeneously expressed following hPSC differentiation (González et al., 2014; Haenebalcke et al., 2013; Mandegar et al., 2016; Ordovas et al., 2015). Overall, there are currently no methods for inducible gene knockout in hPSCs that fulfill all the criteria described above.
