title: Dynamic reprogramming of 5-hydroxymethylcytosine during early porcine embryogenesis.
abstract: DNA active demethylation is an important epigenetic phenomenon observed in porcine zygotes, yet its molecular origins are unknown. Our results show that 5-methylcytosine (5mC) converts into 5-hydroxymethylcytosine (5hmC) during the first cell cycle in porcine in vivo fertilization (IVV), IVF, and SCNT embryos, but not in parthenogenetically activated embryos. Expression of Ten-Eleven Translocation 1 (TET1) correlates with this conversion. Expression of 5mC gradually decreases until the morula stage; it is only expressed in the inner cell mass, but not trophectoderm regions of IVV and IVF blastocysts. Expression of 5mC in SCNT embryos is ectopically distinct from that observed in IVV and IVF embryos. In addition, 5hmC expression was similar to that of 5mC in IVV cleavage-stage embryos. Expression of 5hmC remained constant in IVF and SCNT embryos, and was evenly distributed among the inner cell mass and trophectoderm regions derived from IVV, IVF, and SCNT blastocysts. Ten-Eleven Translocation 3 was highly expressed in two-cell embryos, whereas TET1 and TET2 were highly expressed in blastocysts. These data suggest that TET1-catalyzed 5hmC may be involved in active DNA demethylation in porcine early embryos. In addition, 5mC, but not 5hmC, participates in the initial cell lineage specification in porcine IVV and IVF blastocysts. Last, SCNT embryos show aberrant 5mC and 5hmC expression during early porcine embryonic development.
authors: State Key Laboratory for Agrobiotechnology, College of Biological Science, China Agricultural University, Beijing, China.
authors: Zubing
authors: Z
authors: Cao
authors: Anhui Provincial Laboratory of Local Livestock and Poultry Genetic Resource Conservation and Breeding, College of Animal Science and Technology, Anhui Agricultural University, Hefei, China.
authors: Naru
authors: N
authors: Zhou
authors: Anhui Provincial Laboratory of Local Livestock and Poultry Genetic Resource Conservation and Breeding, College of Animal Science and Technology, Anhui Agricultural University, Hefei, China.
authors: Yu
authors: Y
authors: Zhang
authors: Anhui Provincial Laboratory of Local Livestock and Poultry Genetic Resource Conservation and Breeding, College of Animal Science and Technology, Anhui Agricultural University, Hefei, China.
authors: Yuanliang
authors: Y
authors: Zhang
authors: Anhui Provincial Laboratory of Local Livestock and Poultry Genetic Resource Conservation and Breeding, College of Animal Science and Technology, Anhui Agricultural University, Hefei, China.
authors: Ronghua
authors: R
authors: Wu
authors: Anhui Provincial Laboratory of Local Livestock and Poultry Genetic Resource Conservation and Breeding, College of Animal Science and Technology, Anhui Agricultural University, Hefei, China.
authors: Yunsheng
authors: Y
authors: Li
authors: Anhui Provincial Laboratory of Local Livestock and Poultry Genetic Resource Conservation and Breeding, College of Animal Science and Technology, Anhui Agricultural University, Hefei, China. Electronic address: yunhaizhang@ahau.edu.cn.
authors: Yunhai
authors: Y
authors: Zhang
authors: State Key Laboratory for Agrobiotechnology, College of Biological Science, China Agricultural University, Beijing, China.
authors: Ning
authors: N
authors: Li
mesh_terms: D044503:5-Methylcytosine / Q000378:metabolism / Q000031:analogs & derivatives; D000818:Animals; D003596:Cytosine / Q000031:analogs & derivatives* / Q000378:metabolism; D019175:DNA Methylation; D047108:Embryonic Development / Q000235:genetics*; D053652:Nuclear Transfer Techniques / Q000662:veterinary; D013552:Swine / Q000196:embryology* / Q000235:genetics
chemical_list: C011865:5-hydroxymethylcytosine; D044503:5-Methylcytosine; D003596:Cytosine
keywords: 5-Hydroxymethylation; Active DNA demethylation; Embryo; Pig