Induction of Oct-3/4 expression in somatic cells by gap junction-mediated cAMP signaling from blastomeres.
We report the induction of embryonic gene expression in epithelial HC-11 cells upon communication with blastomeres in compacting mouse embryos. In contrast to NIH3T3 fibroblasts, HC-11 epithelial cells form gap junctions with blastomeres after injection into cleavage-stage embryos, as shown by targeting of phosphorylated connexin43 (pCx43) to areas of cell-to-blastomere contact and dye coupling. This was accompanied by expression of the embrvo-specific transcription factor, Oct-3/4, in the HC-11 cells. Dye coupling and Oct-3/4 expression were abolished with heptanol and 18beta- glycyrrhetinic acid, two gap junction blockers. Oleamide, which blocks gap junction-mediated communication but not electrical conductance, also inhibited Oct-3/4 expression in HC-11 cells, suggesting that Oct-3/4 induction results from transfer of molecules of < 1 kDa through gap junctions. Inhibition of cAMP signaling in blastomeres abolishes Oct-3/4 expression in somatic cells despite gap junction formation. In addition, reprogramming of NIH3T3 fibroblasts in an extract of HC-11 cells enabled assembly of pCx43 and Oct-3/4 expression after contact of the reprogrammed cells with blastomeres. We propose that gap junction-mediated cAMP signaling between blastomeres and somatic cells results in changes in somatic cell gene expression.
Burnside
Amy S
AS
Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA, USA.
Collas
Philippe
P
D016475:3T3 Cells; D000818:Animals; D001757:Blastomeres / Q000502:physiology; D002450:Cell Communication / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D018031:Connexin 43 / Q000502:physiology; D000242:Cyclic AMP / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000187:drug effects / Q000235:genetics; D004622:Embryo, Mammalian; D004847:Epithelial Cells / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D017629:Gap Junctions / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D019850:Heptanol / Q000494:pharmacology; D006993:Hypnotics and Sedatives / Q000494:pharmacology; D015151:Immunoblotting; D051379:Mice; D008854:Microscopy, Electron; D050814:Octamer Transcription Factor-3; D009829:Oleic Acids / Q000494:pharmacology; D014157:Transcription Factors / Q000096:biosynthesis* / Q000187:drug effects / Q000235:genetics
D018031:Connexin 43; D004268:DNA-Binding Proteins; D006993:Hypnotics and Sedatives; D050814:Octamer Transcription Factor-3; D009829:Oleic Acids; C494174:Pou5f1 protein, mouse; D014157:Transcription Factors; C029407:oleylamide; D019850:Heptanol; D000242:Cyclic AMP