Analysis of: HMMR and SAMHD1 i KO s. (A) Table showing the secondary screen CRISPR score of HMMR and SAMHD1 iKOs in HeLa and K562 cells. (B) Representative Z-projected deconvolved immunofluorescence images of mitotic cells of control, HMMR, or SAMHD1 iKO in HeLas treated with nocodazole, paclitaxel, or STLC. Microtubules (DM1α), DNA (DAPI). Scale bar: 9 µm. (C) Percentage of mitotic cells with mitotic defects in control or after iKO of HMMR, treated with either nocodazole (noc), paclitaxel (pac), or STLC, n > 300 cells per condition, across three experimental replicates. (D) Percentage of mitotic cells with mitotic defects after iKO of SAMHD1, treated with nocodazole, paclitaxel, or STLC. n > 300 cells per condition, across three experimental replicates. (E) Quantification of total EB1 immunofluorescence signal in control, HMMR, or SAMHD1 iKO HeLa cells. n = 94, 86, 51 across three experimental replicates. (F) Quantification of total spindle tubulin immunofluorescence in the HMMR and SAMHD1 iKO HeLa cells. n = 61, 69, 62 across three experimental replicates. See Fig. S2 H for representative images. Statistical tests performed: Welch’s t test (***P = <0.001, ****P = <0.0001). Blue lines indicate the median.