Canonical Notch signaling is dispensable for phenylhydrazine-induced stress erythropoiesis. Seven- to 8-week-old RbpJ^fl/flVav^Cre/+ (N = 3-6) and age-matched RbpJ^fl/flVav^+/+ or RbpJ^fl/+Vav^Cre/+ controls (N = 2-3 and 2-3, respectively) were injected with PHZ to induce acute hemolytic anemia. (A) Circulating red blood cell counts in steady-state (day 0) and 2 and 4 days after last PHZ injection. Mean (SD) values are shown. (B-C) Mean (SEM) absolute numbers of E progenitors (PreCFU-E and CFU-E), 4 days after PHZ-induced anemia in BM (B) and spleen (C). *P < .05.