135 DNA METHYLATION PROFILES IN THE PREIMPLANTATION PORCINE EMBRYOS
S. Yeo A , Y.-K. Kang A , D.-B Koo A , J.-S Han A , W.-K Chang B , J.-K. Park B , Y.-M. Han A and K.-K. Lee AA Laboratory of Development and Differentiation, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea. email: dbkoo@kribb.re.kr;
B National Livestock Research Institute, RDA, Suwon, Korea.
Reproduction, Fertility and Development 16(2) 190-190 https://doi.org/10.1071/RDv16n1Ab135
Submitted: 1 August 2003 Accepted: 1 October 2003 Published: 2 January 2004
Abstract
DNA methylation at CpG dinucleotides is an important epigenetic regulation process, which is associated with gene expression without any change in DNA sequence. During early development of the mouse embryo, dynamic changes in DNA methylation of the genome occur. After fertilization, active demethylation occurs on the paternal genome followed by passive demethylation until morula stage and then de novo methylation at the blastocyst stage. This study was designed to investigate changes in DNA methylation of in vivo- and in vitro-fertilized (IVF) porcine embryos. DNA methylation states were observed in preimplantation porcine embryos by using an immunofluorescence method after staining with an antibody against 5-methylcytosine. In contrast to the data from mouse embryos, active demethylation of the genome from the paternal pronucleus was not observed in the porcine embryos. Also, no passive demethylation was detected in in vivo- and IVF-derived embryos until the morula stage. Moreover, differential de novo methylation was not shown on the genome of the inner cell mass. Whole genomes of inner cell mass and trophectoderm cells were fully methylated. Our results demonstrate that DNA methylation of porcine embryos is different from that of mouse embryos during preimplantation development, suggesting that the machinery to regulate DNA methylation may be species-specific in mammals.
