Runx1 P1N and P2neo mutations severely affect definitive hematopoietic progenitor cell numbers at hemogenic sites. (A) Total CFU-Cd14 numbers for P1N mutant embryos and their wild-type littermates. (B) Total CFU-Cd14 numbers for P2neo mutant embryos and their wild-type littermates. At E8.5, concepti (embryo proper and YS) of the same genotype were pooled and cell suspensions generated and plated in Methocult M3434. Data are the mean ± SD of 2 independent experiments performed in triplicate. Total number of embryos analyzed at E8.5: 6 P1+/+ (4-7 sp), 10 P1N/+ (5-10 sp), 6 P1N/N (4-7 sp), 8 P2+/+ (4-8 sp), 21 P2neo/+ (4-8 sp), and 12 P2neo/neo (4-8 sp). At E11.5, the AVU, YS, and FL were dissected and pooled according to genotype. Data are the mean ± SD of 3 independent experiments performed at least in duplicate. Total number of embryos analyzed at E11.5: 11 P1+/+, 8 P1N/+, 4 P1N/N, 11 P2+/+, 29 P2neo/+, and 20 P2neo/neo. *Statistically significant differences in CFU-C numbers between the samples indicated (P < .05; Student t test). Although the difference between P2+/+ and P2neo/neo E11.5 YS was not statistically significant (P = .17, t test; most likely attributable to a wide range in wild-type CFU-C between 405-1873 per e.e.), the difference between the P2neo/+ and P2neo/neo YS was (ie, P = .03; Student t test). e.e. indicates embryo equivalent.
