Fig. 1: CRISPR/Cas9 knockout screens identify a MAP3K7/TAK1 dependency in a subset of GSCs.

A Schematic of drop-out screen using a custom lentiviral sgRNA Epi-library in glioma stem cells. B Volcano plot representing log2 fold change and −log10 adjusted p-value of each sgRNA abundance comparing final (day 38 or day 35) and reference (day 0) time point in U3013MG or G166 GSC. Positive (essential genes) and negative (non-targeting) control sgRNAs are colored in red and blue, respectively. Dotted lines indicate cut-off used for hit selection. C Venn diagram showing overlap of hits identified in the two GSC screens and common essential genes based on DepMap data (Archilles common essential, version 22Q1). Table shows log2 fold change depletion of best sgRNA of the 19 gene hits in GSCs not essential. Ranking was performed based on the median gene dependency score of CRISPR screens from all DepMap cell lines. D Western blot of U3013MG iCas9 cells showing loss of TAK1 protein 72 h after doxycycline(dox)-induced expression of Cas9. E Cartoon depicting experimental setup of competitive growth assay in iCas9 GSCs. F–I Barplot of competitive growth assay in iCas9 GSCs. Percentage of BFP-positive cells in population was measured by flow cytometry and depicted relative to wells without Cas9 induction (- dox) at each passage. sgNC (non-targeting control sgRNA), sgCTR (targeting control sgRNA cutting outside a coding gene), sgPRMT5/sgMCM2 (essential gene positive control sgRNAs). J Competitive growth assay with complementation by overexpression of wild type TAK1, or catalytically inactive TAK1^K36W mutant. K Cumulative growth assay in ctr (sgCTR) and TAK1 knockout cells (sgMAP3K7) with complementation by overexpression of wild type TAK1, or catalytically inactive TAK1^K36W mutant.