Effect of Notch ligands on Hes-1 and Deltex-1. (A) Expression of Hes1 was evaluated in HPCs cultured on Jagged-1 or Delta-1 fibroblasts at indicated time points using real-time RT-PCR. The data are presented as fold increase over the level of Hes1 expression in HPCs cultured on control fibroblasts. Two experiments with the same results were performed. (B) Expression of Deltex-1 was measured in HPCs at indicated time points using real-time RT-PCR. The data are presented as fold increase over the level of Deltex-1 expression in HPCs cultured on control fibroblasts. Two experiments with the same results were performed. (C) HPCs were transduced with Hes1 or Deltex-1 and cultured with GM-CSF for 7 days. The phenotype of transduced GFP-positive cells was evaluated using multicolor flow cytometry. The results of 2 experiments are shown. (D) GFP-positive cells from experiments described in panel C were sorted and used as stimulator of allogeneic lymph node cells. Cell proliferation was evaluated in triplicate using [³H]-thymidine uptake. Two experiments with similar results were performed. (E) Gr-1⁺ ImCs isolated from BM of CD45.2⁺ mice were injected intravenously into CD45.1⁺ recipients as described in Figure 2D. Donors' CD45.2⁺ cells were isolated from spleens and BM of recipients 24 hours after the transfer. RNA was extracted and expression of Hes1 was measured in triplicate in real-time PCR as described in “Materials and methods.” Hes1/18S ratio is shown. Data represent the average ± SE of 3 experiments.