title: Expression and potential role of microRNA-29b in mouse early embryo development.
abstract: OBJECTIVE
  MicroRNA-29b (miR29b) has been previously identified in early mouse embryos through miRNA microarray analysis. Recent research has indicated that miR29b participates in DNA methylation by regulating DNA methyltransferase 3a/3b (Dnmt3a/3b) expression. However, the expression pattern and biological function of miR29b in mouse preimplantation embryonic development remain unknown.
  
  
  METHODS
  In this study, we examined the expression patterns of miR29b and Dnmt3a/3b in mouse early embryos at different developmental stages. Subsequently, expression and localization of DNMT3A/3B protein was analyzed in mouse early embryos by immunofluorescence staining. The biological function of miR29b in mouse early embryos was analyzed by microinjection of commercially available miRNA-specific inhibitors and mimics.
  
  
  RESULTS
  Our data showed that Dnmt3a/3b mRNA expression is negatively regulated by miR29b in mouse early embryos. Immunofluorescence analysis revealed that DNMT3A/3B protein expression is predominantly localized within the nucleoplasm of embryos. Alterations to the activity of miR29b could change the DNA methylation levels in mouse preimplantation embryos and lead to a developmental blockade, from the morula to the blastocyst stage.
  
  
  CONCLUSIONS
  These results indicated a role for the miR29b-Dnmt3a/3b-DNA methylation axis in mouse early embryonic development, and we provide evidence that miR29b is indispensable for mouse early embryonic development. This study contributes to a preliminary understanding of the role of miR29b during mouse embryonic development.
authors.affiliation: Department of Reproduction, Nanjing Maternity and Child Health Care Hospital, Affiliated to Nanjing Medical University, Nanjing Medical University, Nanjing, China.
authors.forename: Junqiang
authors.initials: J
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Liu
authors.forename: Shenglin
authors.initials: S
authors.lastname: Jiang
authors.forename: Chun
authors.initials: C
authors.lastname: Zhao
authors.forename: Rong
authors.initials: R
authors.lastname: Shen
authors.forename: Xirong
authors.initials: X
authors.lastname: Guo
authors.forename: Xiufeng
authors.initials: X
authors.lastname: Ling
authors.forename: Chang
authors.initials: C
authors.lastname: Liu
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000378:metabolism; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000096:biosynthesis / Q000235:genetics*; D019175:DNA Methylation / Q000235:genetics; D000090205:DNA Methyltransferase 3A; D047108:Embryonic Development / Q000235:genetics*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D051379:Mice; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D011247:Pregnancy; D012333:RNA, Messenger / Q000096:biosynthesis; D000097584:DNA Methyltransferase 3B
chemical_list: D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A; D035683:MicroRNAs; D012333:RNA, Messenger; D000097584:DNA Methyltransferase 3B; C000717967:DNMT3A protein, human; C000715535:Dnmt3a protein, mouse; C532045:MIRN29a microRNA, human