FIG. 3.

Growth of blastocysts in culture. Blastocysts were cultured in vitro as described in Materials and Methods. (A) Blastocyst in culture medium immediately after isolation (day 0 in culture). (B and D) Blastocyst in culture for 40 h (day 2). (C and E) Blastocyst in culture for 100 h (day 5). Most blastocysts attached and started to grow at day 2 (B) and showed typical morphology at day 5, including the trophoblastic giant cells (TG) and the inner cell mass (ICM) (C). Putative NRF-1^−/− blastocysts failed to grow (D and E). (B and C) The grown blastocyst was genotyped as NRF-1^+/+. All of the images are at the same magnification.