Effect of gremlin on the activity and survival of AGM hematopoietic cells. (A–C) E11 AGMs cultured as explants in the presence or absence of gremlin (250 ng/ml) were analyzed after long term HSC repopulation assay (A), CFU-S11 assay (B), and CFU-C assay (C). For HSC repopulation, 0.3 AGM cell equivalents were injected per recipient. For each CFU-S11 condition, 14 mice were injected with 1 AGM equivalent (n = 3, *, P = 0.002). For CFU-C, n = 3. P < 0.01 for CFU-Mix. Data represent the mean ± SD. (D) FACS plots showing 7AAD and Annexin V staining of CD45+ cells from AGMs cultured in the absence or presence of gremlin (250 ng/ml). Percentages of cells shown in gated regions. (E) Graphs show absolute numbers of CD45+ cells and Annexin V+ 7AAD+CD45+ cells per AGM (n = 3). (F) Four-color staining dot plots showing percentages of viable cells from AGM explants cultured in the presence or absence of gremlin or Bmp4. (Upper) Cells gated within the CD45− population. (Lower) Cells gated within the total population. C, control; G, gremlin.