title: Specific PKC isoforms regulate blastocoel formation during mouse preimplantation development.
abstract: During early mammalian development, blastocyst morphogenesis is achieved by epithelial differentiation of trophectoderm (TE) and its segregation from the inner cell mass (ICM). Two major interrelated features of TE differentiation required for blastocoel formation include intercellular junction biogenesis and a directed ion transport system, mediated by Na+/K+ ATPase. We have examined the relative contribution of intercellular signalling mediated by protein kinase C (PKC) and gap junctional communication in TE differentiation and blastocyst cavitation. The distribution pattern of four (delta, theta, iota/lambda, zeta) PKC isoforms and PKCmicro/PKD1 showed partial colocalisation with the tight junction marker ZO-1alpha+ in TE and all four PKCs (delta, theta, iota/lambda, zeta) showed distinct TE/ICM staining patterns (predominantly at the cell membrane within the TE and cytoplasmic within the ICM), indicating their potential contribution to TE differentiation and blastocyst morphogenesis. Specific inhibition of PKCdelta and zeta activity significantly delayed blastocyst formation. Although modulation of these PKC isoforms failed to influence the already established programme of epithelial junctional differentiation within the TE, Na+/K+ ATPase alpha1 subunit was internalised from membrane to cytoplasm. Inhibition of gap junctional communication, in contrast, had no influence on any of these processes. Our results demonstrate for the first time that distinct PKC isotypes contribute to the regulation of cavitation in preimplantation embryos via target proteins including Na+/K+ ATPase.
authors.affiliation: Division of Cell Sciences, School of Biological Sciences, University of Southampton, Southampton SO16 7PX, UK. jje@soton.ac.uk
authors.forename: Judith J
authors.initials: JJ
authors.lastname: Eckert
authors.forename: Amanda
authors.initials: A
authors.lastname: McCallum
authors.forename: Andrew
authors.initials: A
authors.lastname: Mears
authors.forename: Martin G
authors.initials: MG
authors.lastname: Rumsby
authors.forename: Iain T
authors.initials: IT
authors.lastname: Cameron
authors.forename: Tom P
authors.initials: TP
authors.lastname: Fleming
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000378:metabolism*; D002450:Cell Communication / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism; D046508:Culture Techniques; D005260:Female; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D009024:Morphogenesis; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D011493:Protein Kinase C / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D019108:Tight Junctions / Q000378:metabolism; D062826:Zonula Occludens-1 Protein; D062827:Zonula Occludens-2 Protein
chemical_list: D007527:Isoenzymes; D008565:Membrane Proteins; D010455:Peptides; D010750:Phosphoproteins; C569043:Tjp1 protein, mouse; C569047:Tjp2 protein, mouse; D062826:Zonula Occludens-1 Protein; D062827:Zonula Occludens-2 Protein; D011493:Protein Kinase C; D000254:Sodium-Potassium-Exchanging ATPase