Features of miR-125b-induced myeloid cancer cells. (A) Leukemic cells from MG-125b are serially transplantable. Cells from MG and MG-125b mice were harvested 3 to 6 months after bone marrow reconstitution. 200K GFP⁺ splenic cells (black dotted line) or 400 to 1000K GFP⁺ BMCs (red line) from MG-125b mice were transferred into secondary sublethally irradiated C57bl/6 recipients. Two million GFP⁺ BMCs from the secondary mice were injected into tertiary nonirradiated C57bl/6 recipients (orange line indicated as “no irradiation”). Death point of the recipients (at least 4 mice per group) were recorded when found dead or moribund. (B) Myeloid cancer cells induced by miR-125b overexpression were harvested and subjected to exome deep-sequencing analysis. Every exon was sequenced an average of 50 times. The sequencing data sets were filtered on a 0.1% false-positive discovery rate and cancer-associated mutations were obtained by excluding those that were identified in normal noncancerous mice. Plot shows the number of cancer-associated exonic mutations identified in each of the 3 independent experiments. (C) Donor BMCs from C57bl/6, Rag1^−/−, and EμMT (B6.129S2-Ighmtm1Cgn/J) mice were transduced with MG-125b retroviruses, which encode for miR-125b and GFP expression. As control, donor BMCs from C57bl/6 animals were transduced with empty MG retroviruses, which encode for GFP. BMCs were transplanted into lethally irradiated C57bl/6 recipients, and the blood of the mice was subjected to flow cytometric analyses 3 months after reconstitution. (D) The survival curve of the mice described in panel C is shown (3 mice per group). Mice were considered dead when they became moribund or found dead.