Proposed model for JARID1B activity in HSC regulation. The box of letters depicts the amino-terminal tail of histone H3. By counteracting the trimethylated status of lysine 4 (H3K4), JARID1B represses “stemness” loci and expression of genes associated with multipotency (brown shaded area). Conversely, knockdown of JARID1B shifts the balance toward the methylated status induced by the MLL/WDR5 complex to sustain multipotency (blue shaded area). Figure adapted from Figure 7 in the article by Cellot et al that begins on page 1545. Professional illustration by Alice Y. Chen.