SLFN14 deficiency results in defective MK differentiation. (A) Example plots of flow cytometry analysis of day 4 differentiated imMKCL cells, indicating the percentage of CD41a⁺, CD42a⁺, and CD41a⁺/CD42a⁺ MK. WT/WT cells were measured at passage weeks 9 and 14, and WT/K219N and K219N/K219N cells were measured at passage weeks 2 and 7. (B) Percentage of CD41a⁺/CD42a⁺ cells over time for 2 clones each of WT/K219N and K219N/K219N cells (left). A trend line with error margins (gray area) was fitted for WT/WT cells measured over 14 weeks in culture and added to the graph. Comparison of mean CD41a⁺/CD42a⁺ cells for WT/WT, WT/K219N, and K219N/K219N cells show a significant decrease in double positive cells in SLFN14-deficient cells, as measured during different passage weeks (right). Boxplots represent the middle 50% of the data points, with 25% outliers as whiskers and the mean as a black horizontal line. All individual data points were added as dots to the graph. P values were determined using the pairwise Wilcoxon test.