miR-29a/b-1-null mice exhibit decreased bone marrow cellularity and significantly reduced numbers of HSPCs. (A) Representative flow cytometric analyses. Each column includes WT littermate, miR-29a/b-1 Het, and miR-29a/b-1-null (KO) mice. Live cells were gated based on propidium iodide exclusion. Prior gates for each subpopulation are indicated on the top of each column. Specific HSPC populations and their frequencies were calculated based on total bone marrow cell counts and were identified as shown. (B) Total bone marrow cell counts were based on bilateral femur cell recoveries. (C-G) Summarized results of bone marrow HSPC frequencies assessed by flow cytometry. The cell populations evaluated were indicated at the x-axis, and the y-axis represents the frequencies of these populations among total bone marrow cells. Each group included 7 to 10 mice. Error bars indicated SEM. Statistical significance was calculated using a Student t test: *P < .05; **P < .01.