title: 5-AZA-2'-deoxycytidine (5-AZA-CdR) leads to down-regulation of Dnmt1o and gene expression in preimplantation mouse embryos.
abstract: 5-AZA-2'-deoxycytidine (5-AZA-CdR) is a demethylating, teratogenic agent and a mutagen, which causes defects in the developing mouse and rat after implantation. Our previous data indicated that 5-AZA-CdR (0.2 and 1.0 muM) inhibited the development of mouse preimplantation embryos. Pronuclear embryos exposed to 5-AZA-CdR at the pronuclear stage were unable to form 8-cell embryos, while 2-cell-stage embryos exposed to 5-AZA-CdR only developed into uncompacted 8-cell-stage embryos. And there was no formation of blastocysts when 4-cell embryos cultured in 5-AZA-CdR. In our present study, we detected Dnmt1o protein and some developmental gene expression in order to find the reasons for the developmental arrest. Dnmt1o could not traffic to 8-cell nuclei as control when embryos were exposed to 5-AZA-CdR. Dnmt1o was in cytoplasm at 2-cell and 4-cell stages before and after treated with 5-AZA-CdR. Gene expression changes were also detected in this research. Our data indicated that connexin 31 (Cx31), connexin 43 (Cx43), connexin 45 (Cx45), E-cadherin (Cdh1) and beta-catenin (Ctnnb1) were all downregulated by 5-AZA-CdR. Cx31, Cx43 and Cx45 are members of connexins family, which have a central role in gap junctions. Cdh1 and Ctnnb1 are necessary for the foundation of tight junctions. Therefore, developmental arrest induced by 5-AZA-CdR may be caused by the failure of Dnmt1o cytoplasmic-nuclear traffic and the down-regulation of developmental gene expression. Normal compaction and blastocoel cavitation need Dnmt1o traffic to 8-cell nuclei and the right gene expression, especially the correlative genes in gap junctions and tight junctions.
authors.affiliation: College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, P.R China.
authors.forename: Jian-Ning
authors.initials: JN
authors.lastname: Yu
authors.forename: Chun-Yang
authors.initials: CY
authors.lastname: Xue
authors.forename: Xu-Guang
authors.initials: XG
authors.lastname: Wang
authors.forename: Fei
authors.initials: F
authors.lastname: Lin
authors.forename: Chun-Yi
authors.initials: CY
authors.lastname: Liu
authors.forename: Fu-Zeng
authors.initials: FZ
authors.lastname: Lu
authors.forename: Hong-Lin
authors.initials: HL
authors.lastname: Liu
mesh_terms: D000818:Animals; D001374:Azacitidine / Q000031:analogs & derivatives* / Q000633:toxicity; D001755:Blastocyst / Q000187:drug effects* / Q000502:physiology; D015820:Cadherins / Q000037:antagonists & inhibitors / Q000378:metabolism; D017630:Connexins / Q000037:antagonists & inhibitors / Q000378:metabolism; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000037:antagonists & inhibitors* / Q000235:genetics; D019175:DNA Methylation; D000077209:Decitabine; D015536:Down-Regulation; D047108:Embryonic Development / Q000187:drug effects*; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000502:physiology; D051379:Mice; D009153:Mutagens / Q000633:toxicity*; D013723:Teratogens / Q000633:toxicity*; D051176:beta Catenin / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D015820:Cadherins; D017630:Connexins; D009153:Mutagens; D013723:Teratogens; D051176:beta Catenin; D000077209:Decitabine; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; C000619381:Dnmt1 protein, mouse; D001374:Azacitidine