title: Expression of ZO-1 and occludin at mRNA and protein level during preimplantation development of the pig parthenogenetic diploids.
abstract: Expression of mRNAs and proteins of ZO-1 and occludin was analyzed in pig oocytes and parthenogenetic diploid embryos during preimplantation development using real-time RT-PCR, western blotting and immunocytochemistry. All germinal vesicle (GV) and metaphase (M)II oocytes and preimplantation embryos expressed mRNAs and proteins of ZO-1 and occludin. mRNA levels of both ZO-1 and occludin decreased significantly from GV to MII, but increased at the 2-cell stage followed by temporal decrease during the early and late 4-cell stages. Then, both mRNAs increased after compaction. Relative concentration of zo1α- was highest in 2-cell embryos, while zo1α+ was expressed from the morula stage. Occludin expression greatly increased after the morula stage and was highest in expanded blastocysts. Western blotting analysis showed constant expression of ZO-1α- throughout preimplantation development and limited translation of ZO-1α+ from the blastocysts, and species-specific expression pattern of occludin. Immunocytochemistry analysis revealed homogeneous distribution of ZO-1 and occludin in the cytoplasm with moderately strong fluorescence in the vicinity of the contact region between blastomeres, around the nuclei in the 2-cell to late 4-cell embryos, and clear network localization along the cell-boundary region in embryos after the morula stage. Present results show that major TJ proteins, ZO-1 and occludin are expressed in oocytes and preimplantation embryos, and that ZO-1α+ is transcribed by zygotic gene activation and translated from early blastocysts with prominent increase of occludin at the blastocyst stage.
authors.affiliation: Department of Bioresource Sciences, Graduate School of Science and Technology, Kobe University, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Shangdan
authors.initials: S
authors.lastname: Xu
authors.forename: Jibak
authors.initials: J
authors.lastname: Lee
authors.forename: Masashi
authors.initials: M
authors.lastname: Miyake
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000502:physiology*; D004171:Diploidy; D004591:Electrophoresis, Polyacrylamide Gel; D018507:Gene Expression Regulation, Developmental; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008677:Metaphase; D009028:Morula / Q000166:cytology / Q000502:physiology; D062793:Occludin; D009865:Oocytes / Q000502:physiology*; D010312:Parthenogenesis / Q000235:genetics*; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger; D013552:Swine; D019108:Tight Junctions / Q000235:genetics; D062826:Zonula Occludens-1 Protein
chemical_list: D008565:Membrane Proteins; D062793:Occludin; D010750:Phosphoproteins; D012333:RNA, Messenger; D062826:Zonula Occludens-1 Protein