Cell adhesion and gap junction formation in the early mouse embryo are induced prematurely by 6-DMAP in the absence of E-cadherin phosphorylation.
Compaction of the mouse embryo, which takes place at the 8-cell stage, is dependent upon the adhesion molecule E-cadherin (uvomurulin), but does not require protein synthesis, suggesting that post-translational modification(s) is (are) implicated in the setting up of this phenomenon. The demonstration recently that E-cadherin is phosphorylated at the 8-cell stage just before compaction supports this theory. In this work we used 6-dimethylaminopurine, a serine-threonine kinase inhibitor, to investigate the role of protein phosphorylation in compaction of mouse embryos. 6-dimethylaminopurine is able to induce cell flattening and gap junction formation prematurely at the 4-cell stage; however, it does not induce cell surface polarization, as occurs during normal compaction. 6-dimethylaminopurine-induced premature flattening is inhibited when the embryos are cultured in the presence of an anti-E-cadherin antibody or without extra-cellular Ca2+, demonstrating that this process requires functional E-cadherin; whereas cell flattening and gap junction formation take place in the absence of E-cadherin phosphorylation, suggesting that its phosphorylation is not required normally for these events. The relationship between E-cadherin-mediated cell flattening and gap junction formation during compaction is discussed.
Aghion
J
J
Département de Biologie du Développement, Institut Jacques Monod, CNRS-Université Paris VII-Denis Diderot, France.
Gueth-Hallonet
C
C
Antony
C
C
Gros
D
D
Maro
B
B
D000225:Adenine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D001757:Blastomeres / Q000187:drug effects / Q000648:ultrastructure; D015820:Cadherins / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects*; D002450:Cell Communication / Q000187:drug effects; D016764:Cell Polarity / Q000187:drug effects; D004622:Embryo, Mammalian / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D005260:Female; D017629:Gap Junctions / Q000187:drug effects* / Q000648:ultrastructure; D051379:Mice; D008855:Microscopy, Electron, Scanning; D010766:Phosphorylation; D011247:Pregnancy; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors
D015820:Cadherins; C001020:N(6),N(6)-dimethyladenine; D017346:Protein Serine-Threonine Kinases; D000225:Adenine