Figure 1.
CYB561A3 is essential for the proliferation of Burkitt lymphoma cells. (A) Scatterplots showing the statistical significance of selected top hits that were selectively important for P3HR-1 Burkitt vs GM12878 LCLs. Statistical significance was quantitated by the STARS algorithm, using 2 biological replicates for each axis. (B) Distribution of Avana human genome-wide CRISPR screen sgRNA log2 fold-change values at day 21 vs input in Cas9+ P3HR-1 Burkitt lymphoma (left) or GM12878 LCL (right). Values for CYB561A3 and CYB561 targeting sgRNAs (red lines) are overlaid on gray gradients depicting all Avana sgRNA library values.30 Average day 21 vs input values from 4 screen biological replicates are shown. (C) DepMap CRISPR screen dependency scores34 for sgRNAs targeting CYB561A3 across cell lines from the indicated cancer cells of origin. Circles represent DepMap screen values for cell lines from the tissue of origin indicated at right. Negative values indicate selection against sgRNAs targeting CYB561A3 over a 21-day growth and survival screen. Values less than −1 (red vertical line) indicate the DepMap cutoff for CYB561A3 dependency. (D) Growth curve analysis of Cas9+ P3HR-1 (top) and GM12878 (bottom) with control or independent CYB561A3 sgRNAs, as indicated. (E) Indel-sequencing analysis of Cas9 activity at the CYB561A3 locus. Shown are the percentage of indels in P3HR-1 or GM12878 cells expressing the indicated control or CYB561A3 sgRNAs. (F) Growth curve analysis of Cas9+ P3HR-1 after expression of the indicated green fluorescent protein (GFP) control or CYB561A3R cDNAs and control or CYB561A3 sgRNA, as indicated. (G) Fold change live cell number of Mutu Burkitt cells with EBV latency I or III (Mutu I and III) from days 4 to 8 postexpression of CYB561A3 vs control sgRNAs. (H) Fold change live cell numbers of Kem I EBV latency I Burkitt and Kem III EBV latency III LCLs from days 4 to 8 postexpression of CYB561A3 vs control sgRNAs. (I) Fold-change live cell numbers from EBV+ Akata Burkitt cells with EBV latency I vs EBV– Akata from days 4 to 8 postexpression of CYB561A3 vs control sgRNAs. Mean ± standard deviation fold-change values from n = 3 biological replicates (E-I). *P < .05; **P < .01; ***P < .001. ns, nonsignificant (unpaired Student t test).