Knockdown of L3MBTL1 induces further erythroid differentiation of K562 erythroleukemia cells. (A) K562 cells, grown in RPMI medium supplemented with 10% fetal bovine serum, without exogenous cytokines or hemin, were infected with lentiviral constructs targeting luciferase (shLUC) or L3MBTL1 (sh1 and sh2). GFP⁺ cells, sorted by FACS at 72 hours after infection, were analyzed for GlyA expression by flow cytometry. (B) GFP⁺ K562 cells, before and after exposure to hemin (50μM) for 4 days, were stained with benzidine to assess their Hb content. (C) K562 cells were treated with 50μM hemin for 4 days and the L3MBTL1 mRNA level assessed in the hemin-exposed versus the nontreated cells by quantitative RT-PCR (n = 3).