In vitro and in vivo self-renewal capacity of Tet2-mutant FL hematopoietic stem/ progenitor cells and myeloid progenitors. FL cells were obtained from E14.5 embryos of WT (Tet2^+/+) and Tet2^gt/gt mice. (A) LSK and CMP (Lin⁻Sca-1⁻c-Kit⁺IL7Rα⁻CD34⁺FcγRII/III^low) cells were sorted by flow cytometry (fluorescence-activated cell sorter [FACS]) and plated in methylcellulose media (MethoCult M3434; StemCell Technologies). Cells were cultured for 7 days before enumeration of colony numbers. Numbers of colonies from 500 FL-LSK cells (upper panel) or 1000 FL-CMP cells (lower panel) are shown. Upon replating, cells were recovered from dishes, counted, and plated in methylcellulose at 500 cells per dish for the LSK group and 1000 cells per dish for the CMP group, respectively. Data are the mean ± standard deviation (SD) (n = 3). (B) Five hundred CD150⁺LSK cells (Ly5.2) (upper panel) or 5000 CMP cells (Ly5.2) (lower panel) were sorted by FACS and transplanted into lethally (950 rads) irradiated primary recipients (Ly5.1) with 2 × 10⁵ competitor bone marrow (BM) cells (Ly5.1). For secondary and tertiary transplantation, 2 × 10⁶ whole BM cells taken from the primary or secondary recipients at 12 weeks after transplantation were transplanted into lethally irradiated recipient mice (Ly5.1). Percentages of donor chimerism in recipients’ peripheral blood (PB) were assessed by FACS at 4, 8, and 12 weeks after transplantation. Data are shown as the mean ± SD (n = 3-5). Statistical analyses were performed by unpaired Student t test. P < .05 was considered statistically significant. N.S., not significant.