(A)In vitro screening methodology. Lymphoma cells were partially infected with 48 pools of 48 distinct shRNAs, treated with taxol (4, 6, and 8nM) and monitored using GFP-based flow cytometry for changes in the relative percentage of shRNA-containing (GFP+) cells. Genomic DNA from enriched pools was subsequently subjected to shRNA-specific PCR and sequenced to determine relative shRNA abundance. (B) An in vitro GFP competition assay comparing relative taxol sensitivity in cells infected with two distinct shRNAs targeting Nek4 (6nM taxol, 48h post-treatment; n=5 for all samples). (C) qRT-PCR (n≥3) and western blot analysis of Nek4 expression in lymphoma cells. (D) Partially-transduced lymphoma cells were separately treated with doxorubicin (10ng/ml), cisplatin (7.5ng/ml), 5-fluorouracil (40ng/ml) and vincristine (1.5nM) at similar levels of cytotoxicity (~90% cell death at 48h). The percentage of GFP+ cells was determined 48 hours post treatment (n=3 for doxorubicin, 5-FU, cisplatin, and n=5 for vincristine treatments). Values are shown with standard deviations (s.d.). P-values were determined using a Student’s t-test.