Uterine CD34⁺/c-kit⁻ population exhibits hemangioblast-like potential in vitro. A single uterine blast (A) was plated in differentiation media in 1 well of a 96-well plate. Adherent cells (red; B-C) and nonadherent cells (blue; B,D) were observed after 12 days of culture. Nonadherent and adherent cells were collected separately for RT-PCR analysis of mRNA expression (Flk-1, CD31, β-H1, β-Major, GATA1, and SCL; GAPDH represents the housekeeping gene) (E). Representative micrographs illustrating expression of hematopoietic markers (CD45, Mac-3, CD13, CD16, CD4, and CD8) by the nonadherent cells (F, white arrows), and endothelial markers (CD31, factor VIII [FVIII]) and uptake of DiI-Ac-LDL by the adherent cells (G, white arrows). Rt- or Rb-IgG indicates rat or rabbit IgG negative control, respectively; DAPI (4,6-diamidino-2-phenylindole), nuclear stain. Tubular structures (H, white arrows) were formed by the adherent cells on Matrigel (original magnification ×100). Representative micrographs illustrating Giemsa-May-Grünwald–stained cytospin preparations of cells generated from the nonadherent uterine blast cells. Several different hematopoietic-like phenotypes were observed (I).