Efficient genome editing in erythroid cells unveils novel MYB target genes and regulatory functions

Targeted genome editing holds great promise in biology. However, efficient genome modification, including gene knock-in, remains an unattained goal in multiple cell types and loci due to poor transfection efficiencies and low target genes expression, impeding the positive selection of recombined cells. Here, we describe a genome editing approach to achieve efficient gene targeting using hard to transfect erythroid cell lines. We demonstrate robust fluorescent protein knock-in efficiency in low expressed transcription factor gene loci (e.g. Myb or Zeb1). We further show the ability to target several genes in individual cells, exemplified by MYB-GFP and NuMA-Cherry double knock-in, allowing multicolor labeling of regulatory factors at physiological endogenous levels. Our knock-in tagging approach allowed us to perform genome-wide TF analysis at increased signal-to-noise ratios, and highlighted previously unidentified MYB target genes and pathways. Overall, we establish a versatile CRISPR-Cas9-based platform, offering attractive opportunities for the dissection of the erythroid differentiation process. CUT&RUN