Fig. 5.

Neither induction nor blockage of embryonic compaction affects the activation of Cdx2 expression. (A) Premature compaction induced within 30 minutes of treatment with the PKC agonist DiC8 (right). Normal 4-cell stage mouse embryos are shown on the left, with obvious, individual blastomeres. (B) Cdx2 expression (red) could not be detected by immunocytochemistry 18 hours after DiC8 treatment. Nuclei are blue (DAPI) and Oct4 (a positive control for transcriptional activity of the treated embryos) green. (C) Compaction was inhibited by anti-E-cadherin (ECCD-1) antibody treatment for 24 hours (right). Normally compacted 14-cell stage embryos are shown on the left. (D) Cdx2 was detected (arrowhead) in uncompacted 12-cell stage embryos. Heavy cytoplasmic background (especially around the cell surface) was due to cross-reaction of ECCD-1 (rat IgG monoclonal), which was used at a very high concentration (200 μg/ml) to block embryo compaction, with the Cdx2 antibody (mouse IgG monoclonal).