Overexpression of miR-29a, but not miR-29b, rescues the self-renewal defect in miR-29a/b-1-null HSCs. Transcript levels of miR-29 members were measured in (A) c-Kit-enriched cells. (B) Methylcellulose colony forming capability of LSK cells after retroviral overexpression of miR-29a or miR-29b in miR-29a/b-1-null HSPCs. Twenty-four hours following transduction, GFP⁺ cells were sorted, and 300 were plated per well. Each group represents experiments using 2 mice, with wells plated in triplicate. (C) Transplantation of 300 000 LSK cells from WT or miR-29a/b-1-null HSPCs retrovirally transduced with miR-29a, -29b, or GFP control (n = 6-10 mice per group). Peripheral blood analysis was performed 16 weeks after transplantation. Data represent the aggregate of 2 independent experiments. Error bars indicate SEM. Statistical significance was calculated using a Student t test: *P < .05.