The Lin28b–let-7–Hmga2 axis determines the higher self-renewal potential of fetal haematopoietic stem cells

Fetal haematopoietic stem cells (HSCs) display higher self-renewal potential than their adult counterparts. Eaves and colleagues show that adult HSCs express lower levels of Lin28b and higher levels of let-7 miRNA. They demonstrate that Lin28 overexpression, as well as that of Hmga2 (a target of let-7), induces fetal properties in adult HSCs. Conversely, HMGA2 loss in fetal HSCs results in premature induction of adult HSC self-renewal properties.