MYC and BCL2 mediate the function of YBX1 in leukemia cells. (A-C) Gene set enrichment analysis plots showing enrichment of MYC targets and genes for oxidative phosphorylation in YBX1^high vs YBX1^low groups from GSE14468 and TCGA AML patient cohorts. (D) Immunoblot for Myc and Bcl2 expression in WT and Ybx1^cKO leukemia cells (Gapdh was used as a loading control). (E-F) Immunoblot for MYC and BCL2 expression in MOLM-13 cells (E) and THP-1 cells (F) 4 days after transduction with the indicated lentiviruses (GAPDH was used as a loading control). (G) The mRNA half-life of Myc and Bcl2 in WT and Ybx1^cKO leukemia cells. (H) IGV tracks that show the distribution of m⁶A peaks for Myc and Bcl2 transcripts. (I) MeRIP-qPCR analysis of m⁶A enrichment of Myc and Bcl2 in LICs. Primers 1, 2, and 3 are located around m⁶A sites. (J) YBX1 RIP-qPCR analysis showing YBX1 binding to MYC and BCL2 mRNA in shControl or shIGF2BP1 leukemia cells. (K) Colony formation assay of LICs from WT and Ybx1^cKO AML mice. Ybx1^cKO LICs were transduced with lentiviruses expressing Myc or Bcl2. (L) Representative images from a colony formation assay indicating lentiviruses. Original magnification, ×100. (M-N) Growth curve (M) and colony formation assay (N) of MOLM-13 cells after transduction with indicated lentiviruses. (O) Flow cytometry analysis of apoptosis after transduction with indicated lentiviruses at day 4. (P) Percentages of apoptotic leukemia cells after transduction at day 4. (Q) Working model showing the role of YBX1 in leukemia. Panels D-G and I-P show 1 representative of at least 3 independent experiments. Two-tailed Student t test: *P < .05; **P < .01; ***P < .001. FDR, false discovery rate; NES, normalized enrichment score.