Fig. 6. In vitro culture of PGCs from Pten mutant mice. (A) Increased proliferation of E11.5 PGCs from Pten mutant mice. Cell suspensions of E11.5 gonads were seeded on Sl/Sl⁴-m220 feeder cells that expressed the membrane-bound form of SCF, and cultured in the presence or absence of LIF and bFGF. Changes in PGC number (%) were calculated by dividing the number of PGCs at day 3 by the number of seeded PGCs. Data are mean±s.d. (*P<0.005, P<0.05). (B) EG cell colonies formed in the presence of LIF and bFGF at day 6 after seeding. EG cells were visualized by alkaline phosphatase staining. (C) Increased EG cell production in E11.5 PGCs from Pten mutant mice. Multi-layered colonies that contained more than 20 cells were counted as EG cell colonies, as described previously (Koshimizu et al., 1996). The EG colony-forming efficiency (%) was calculated by dividing the number of EG cell colonies at day 6 by the number of seeded PGCs. The values for individual mice are plotted (P<0.01).