FIG. 3.

Embryonic lethality of Ndel1-null mutants. (A) Homozygous mutants of Ndel1 were not observed, suggesting that null mutants are embryonic lethal. Normal (left) and degenerated deciduas (right) resulting from the Ndel1^+/− cross were sectioned at E5.5 and stained with hematoxylin and eosin. ec, ectoplacental cone; ee, extra-embryonic ectoderm; e, epiblast. (B) Wild-type (upper) and homozygous (lower) blastocysts were isolated from a heterozygous cross and cultured. Both blastocysts hatched and differentiated into trophoblast (tr) and inner cell mass (ICM). The inner cell mass of homozygotes exhibited poor growth and degenerated. (C) Quantitation of the amount of Ndel1 expression in the various genotypes. Northern blot (left side) and Western blot (right side) are shown. Expression was calculated by densitometry compared to the wild type. We repeated three independent experiments, and the results were highly reproducible. (D) Expression of LIS1 or NDEL1 in Ndel1 KO mice or Lis1 KO mice was examined. Total protein was extracted from a brain of E15.5 embryo and subjected to Western blotting. There was no obvious difference in LIS1 or NDEL1 expression in Ndel1 or Lis1 KO mice, respectively.