title: Coxsackievirus and Adenovirus Receptor, a Tight Junction Protein, in Peri-Implantation Mouse Embryos.
abstract: To understand the role of Coxsackievirus and adenovirus receptor (CAR), a tight junction (TJ) protein, in peri-implantation embryos, developmental expression of CAR and its role in paracellular permeability were examined in mouse embryos. Splice variants for transmembrane CAR, Car1, Car2, and Car3 mRNA, were expressed from 2-cell, morula, and blastocyst stages onward, respectively, whereas mRNA for soluble CAR was expressed in MII oocytes and 4-cell stage onward. On Western blot, ∼46 kDa CAR proteins were detected in blastocysts. During the 4-cell embryos to morula stage, CAR was gradually concentrated at the contacts between blastomeres. In blastocysts, CAR was expressed at the cell contacts within the inner cell mass as well as in the trophectoderm (TE) where CAR was found together with ZO1 at the apical contacts, suggesting that CAR builds up apical TJs in TE and mediates cell adhesion in TE and inner cell mass. In blastocysts, CAR-blocking antibodies under Ca(2+) switching increased the dextran permeability and decreased the volume of blastocoel and H19 and Cdx2 mRNA, suggesting the pivotal role of CAR in the blastocyst development and paracellular permeability barrier in TE. CAR was expressed in TE of implanting embryos as well as endometrial epithelium, suggesting the involvement of CAR in the interaction between implanting embryos and endometrium. At 5-6 days postcoitum, CAR was expressed together with ZO1 in the primitive endoderm, visceral endoderm, and epiblasts facing the pro-amniotic cavity, suggesting that CAR TJs contribute to the separation of epiblast from the blastocoel and development of the pro-amniotic cavity within epiblasts.
authors.affiliation: Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, Korea.
authors.forename: Yeong Seok
authors.initials: YS
authors.lastname: Oh
authors.affiliation: Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, Korea.
authors.forename: Won Heum
authors.initials: WH
authors.lastname: Nah
authors.affiliation: Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, Korea.
authors.forename: Bomi
authors.initials: B
authors.lastname: Choi
authors.affiliation: Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, Korea seokhyun@snu.ac.kr.
authors.forename: Seok Hyun
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, Korea mcgye@hanyang.ac.kr.
authors.forename: Myung Chan
authors.initials: MC
authors.lastname: Gye
mesh_terms: D000818:Animals; D062727:Coxsackie and Adenovirus Receptor-Like Membrane Protein / Q000378:metabolism*; D010064:Embryo Implantation / Q000502:physiology*; D004622:Embryo, Mammalian / Q000378:metabolism*; D047108:Embryonic Development / Q000502:physiology; D004707:Endoderm / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D051379:Mice; D009865:Oocytes / Q000378:metabolism; D020033:Protein Isoforms / Q000378:metabolism; D019108:Tight Junctions / Q000378:metabolism*; D062826:Zonula Occludens-1 Protein / Q000378:metabolism
chemical_list: C568772:CLMP protein, mouse; D062727:Coxsackie and Adenovirus Receptor-Like Membrane Protein; D020033:Protein Isoforms; D062826:Zonula Occludens-1 Protein
keywords: CAR; mouse; peri-implantation embryo; tight junction