title: Ascorbic acid increases demethylation in somatic cell nuclear transfer embryos of the pig (Sus scrofa).
abstract: OBJECTIVE
  Investigated the effect and mechanism of ascorbic acid on the development of porcine embryos produced by somatic cell nuclear transfer (SCNT).
  
  
  METHODS
  Porcine embryos were produced by SCNT and cultured in the presence or absence of ascorbic acid. Ten-eleven translocation 3 (TET3) in oocytes was knocked down by siRNA injection. After ascorbic acid treatment, reprogramming genes were analyzed by realtime reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, relative 5-methylcytosine and 5-hydroxymethylcytosine content in pronucleus were detected by realtime PCR.
  
  
  RESULTS
  Ascorbic acid significantly increased the development of porcine embryos produced by SCNT. After SCNT, transcript levels of reprogramming genes,Pou5f1,Sox2, andKlfwere significantly increased in blastocysts. Furthermore, ascorbic acid reduced 5-methylcytosine content in pronuclear embryos compared with the control group. Knock down of TET3 in porcine oocytes significantly prevents the demethylation of somatic cell nucleus after SCNT, even if in the presence of ascorbic acid.
  
  
  CONCLUSIONS
  Ascorbic acid enhanced the development of porcine SCNT embryos via the increased TET3 mediated demethylation of somatic nucleus.
authors.affiliation: National Institute of Animal Science, RDA, Wanju 55365, Korea.
authors.forename: Minghui
authors.initials: M
authors.lastname: Zhao
authors.affiliation: National Institute of Animal Science, RDA, Wanju 55365, Korea.
authors.forename: Tai-Young
authors.initials: TY
authors.lastname: Hur
authors.affiliation: National Institute of Animal Science, RDA, Wanju 55365, Korea.
authors.forename: Jingu
authors.initials: J
authors.lastname: No
authors.affiliation: National Institute of Animal Science, RDA, Wanju 55365, Korea.
authors.forename: Yoonseok
authors.initials: Y
authors.lastname: Nam
authors.affiliation: National Institute of Animal Science, RDA, Wanju 55365, Korea.
authors.forename: Hyeunkyu
authors.initials: H
authors.lastname: Kim
authors.affiliation: National Institute of Animal Science, RDA, Wanju 55365, Korea.
authors.forename: Gi-Sun
authors.initials: GS
authors.lastname: Im
authors.affiliation: National Institute of Animal Science, RDA, Wanju 55365, Korea.
authors.forename: Seunghoon
authors.initials: S
authors.lastname: Lee
keywords: Ascorbic Acid; Demethylation; Porcine; Somatic Cell Nuclear Transfer (SCNT); Ten-eleven Translocation 3 (TET3)