Figure 1. The majority of pre-B1 cells are derived at E13.5–E15.5.

A) Timed-pregnant hGFAP::GFP female mice received two injections of BrdU at E12.5, E14.5, E16.5, or combined E17.5/E18.5, and whole-mounts of the V-SVZ in the offspring were analyzed 21d after birth. B) The number of GFP⁺/BrdU⁺ cells was significantly higher in mice injected at E14.5 compared to other ages. Many of the ependymal cells were also BrdU-labeled at E14.5, as previously shown (Spassky et al., 2005). C) Quantification of V-SVZ GFP⁺/BrdU⁺ cells from animals injected at different timepoints. Data are expressed as mean ± s.e.m., n=6/stage, three independent experiments each (*** p<0.0001). D) NIT-GFP retroviruses were intraventricularly delivered into CD1 embryos at E12.5, E13.5, E15.5, E17.5 or P0. Injected animals received BrdU for one week at P28 and their OB were analyzed 3 weeks later. E) The majority of GFP⁺/BrdU⁺ OB neurons were derived from retroviral injections at E15.5. F) Quantification of GFP⁺/BrdU⁺ cells in the OB of animals injected at different stages. Data are expressed as mean ± s.e.m., n=12 (E12.5), n=6 (E13.5), n=16 (E15.5), n=11 (E17.5), n=4 (P0), three independent experiments each stage (*** p<0.0001). Scale bars represent 50 μm in B and E. See also Figure S1.