Beta-catenin is a major tyrosine-phosphorylated protein during mouse oocyte maturation and preimplantation development.
During mouse preimplantation development, the components of the E-cadherin-catenin complex are derived from both maternal and zygotic gene activity and the adhesion complex is increasingly accumulated and stored in a nonfunctional form, ready to be used for compaction and the formation of the trophectoderm cell layer (Ohsugi et al., Dev. Dyn. 206:391-402, 1996). Here, we show that beta-catenin is a major tyrosine-phosphorylated protein in oocytes and early cleavage-stage embryos and that the relative amount of phosphorylated beta-catenin is greatly reduced during the morula-blastocyst transition. Peptide-specific antibodies indicate that beta-catenin undergoes conformational changes and/or that the carboxy-terminal region of beta-catenin is blocked during preimplantation development. Moreover, the availability of a carboxy-terminal epitope seems to depend on the tyrosine phosphorylation state of beta-catenin and becomes unmasked when oocytes are treated with the tyrosine kinase inhibitor genistein. Our results suggest that tyrosine phosphorylation of beta-catenin represents a molecular mechanism to keep the accumulating E-cadherin adhesion complex in a nonfunctional form. Dev Dyn 1999;216:168-176.
Ohsugi
M
M
Department of Molecular Embryology, Max-Planck Institute of Immunobiology, Freiburg, Germany.
Butz
S
S
Kemler
R
R
D000818:Animals; D015820:Cadherins / Q000737:chemistry / Q000502:physiology; D003598:Cytoskeletal Proteins / Q000737:chemistry* / Q000502:physiology*; D047108:Embryonic Development / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D000939:Epitopes; D005260:Female; D019833:Genistein / Q000494:pharmacology; D007150:Immunohistochemistry; D051379:Mice; D008815:Mice, Inbred Strains; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation; D011233:Precipitin Tests; D011247:Pregnancy; D011487:Protein Conformation; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D015534:Trans-Activators; D014443:Tyrosine / Q000378:metabolism*; D051176:beta Catenin
C495267:CTNNB1 protein, mouse; D015820:Cadherins; D003598:Cytoskeletal Proteins; D004791:Enzyme Inhibitors; D000939:Epitopes; D015534:Trans-Activators; D051176:beta Catenin; D014443:Tyrosine; D019833:Genistein; D011505:Protein-Tyrosine Kinases