title: EZH2 is essential for development of mouse preimplantation embryos.
abstract: Enhancer of zeste homologue 2 (Ezh2) is essential for the development of the early mouse preimplantation embryo. Loss of Ezh2 results in embryonic lethality in mice. Ezh2-deficient embryos display impaired outgrowth potential, defective establishment of Ezh2-null embryonic stem (ES) cells and adherence and differentiation of the trophoblast layer into giant cells. We investigated if Ezh2 controls the fate of embryos at an earlier stage by treating with cycloheximide (CHX) or microinjecting short interfering RNA (siRNA) to restrict embryonic Ezh2 expression during preimplantation. CHX inhibited de novo EZH2 protein synthesis in zygotes, suggesting that EZH2 requires de novo synthesis during post-fertilisation stages. We found that loss of Ezh2 at the pronuclear stage caused severe growth retardation and reduced blastocyst formation. Expression of the pluripotency-associated markers Oct4, Sox2 and Nanog were significantly decreased in embryos that had been injected with Ezh2 siRNA. In addition, Ezh2 loss induced upregulated expression of genes related to the differentiation of germ layers, including Gata6, Hoxb1 and Hand1. Finally, apoptosis was increased in the blastocyst embryos with Ezh2 knockdown. Modification of histone H3-Lysine 27 de-methylation and tri-methylation (H3K27me2/3) was strongly reduced in Ezh2 siRNA embryos. We conclude that Ezh2 is essential for early preimplantation embryo development through the regulation of epigenetic modification and apoptosis.
authors.affiliation: College of Animal Science and Technology, Nanjing Agricultural University, Weigang No.1, Nanjing 210095, China.
authors.forename: Xian-Ju
authors.initials: XJ
authors.lastname: Huang
authors.affiliation: College of Animal Science and Technology, Nanjing Agricultural University, Weigang No.1, Nanjing 210095, China.
authors.forename: Xuguang
authors.initials: X
authors.lastname: Wang
authors.affiliation: College of Animal Science and Technology, Nanjing Agricultural University, Weigang No.1, Nanjing 210095, China.
authors.forename: Xueshan
authors.initials: X
authors.lastname: Ma
authors.affiliation: College of Animal Science and Technology, Nanjing Agricultural University, Weigang No.1, Nanjing 210095, China.
authors.forename: Shao-Chen
authors.initials: SC
authors.lastname: Sun
authors.affiliation: College of Animal Science and Technology, Nanjing Agricultural University, Weigang No.1, Nanjing 210095, China.
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Zhou
authors.affiliation: College of Animal Science and Technology, Nanjing Agricultural University, Weigang No.1, Nanjing 210095, China.
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Zhu
authors.affiliation: Corresponding author. Email:
authors.forename: Honglin
authors.initials: H
authors.lastname: Liu
mesh_terms: D000818:Animals; D017209:Apoptosis; D001755:Blastocyst / Q000378:metabolism*; D002454:Cell Differentiation; D046149:Embryo Culture Techniques; D047108:Embryonic Development; D000071221:Enhancer of Zeste Homolog 2 Protein; D044127:Epigenesis, Genetic; D005307:Fertilization in Vitro; D018507:Gene Expression Regulation, Developmental; D005865:Gestational Age; D006657:Histones / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D008745:Methylation; D008813:Mice, Inbred ICR; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000378:metabolism; D009865:Oocytes / Q000378:metabolism; D063151:Polycomb Repressive Complex 2 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D055748:SOXB1 Transcription Factors / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D006657:Histones; D018398:Homeodomain Proteins; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D055748:SOXB1 Transcription Factors; C527783:Sox2 protein, mouse; D000071221:Enhancer of Zeste Homolog 2 Protein; C498410:Ezh2 protein, mouse; D063151:Polycomb Repressive Complex 2