title: Exogenous expression of OCT4 facilitates oocyte-mediated reprogramming in cloned porcine embryos.
abstract: OCT4 is a well-established regulator of pluripotency and nuclear reprogramming. To determine if improving OCT4 abundance can facilitate oocyte-mediated reprogramming in cloned porcine embryos, we artificially increased OCT4 levels by co-incubating donor cells with 50 ng/µl OCT4 plasmid. We observed higher rates of blastocyst formation (P < 0.05) and lower levels of blastocyst apoptosis in nuclear-transfer-derived embryos carrying OCT4-incubated donor nuclei (OCT4-SCNT). The beneficial effect caused by exogenous expression of OCT4 involves epigenetic changes, wherein increased histone acetylation (AcH3K9) appeared in OCT4-SCNT embryos at the one-cell and blastocyst stages and reduced histone methylation (H3K9me2) was observed at the one-cell stage (P < 0.05). There was a transient increase in exogenous OCT4 and an up-regulation of endogenous OCT4 level in OCT4-SCNT embryos (P < 0.05), while the expression pattern of epigenetic enzymes was changed. These modifications were accompanied by an up-regulation of CDX2, whose interaction with OCT4 is instrumental for implantation, and a down-regulation of XIST, a negative indicator of reprogramming (P < 0.05). Taken together, our results support a role for exogenous expression of OCT4 in improving the efficiency of nuclear reprogramming while establishing a convenient and timesaving method to improve nuclear-transfer outcomes.
authors.affiliation: State Key Laboratory of Biocontrol, Sun Yat-Sen University, Guangzhou, P. R. China.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Ji
authors.forename: Peiqing
authors.initials: P
authors.lastname: Cong
authors.forename: Haijing
authors.initials: H
authors.lastname: Zhao
authors.forename: Zhenwei
authors.initials: Z
authors.lastname: Song
authors.forename: Guangyin
authors.initials: G
authors.lastname: Zhao
authors.forename: Jintao
authors.initials: J
authors.lastname: Gao
authors.forename: Yu
authors.initials: Y
authors.lastname: Nie
authors.forename: Yaosheng
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001755:Blastocyst / Q000378:metabolism / Q000502:physiology*; D065150:Cellular Reprogramming / Q000502:physiology*; D044127:Epigenesis, Genetic / Q000187:drug effects; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D053652:Nuclear Transfer Techniques; D050814:Octamer Transcription Factor-3 / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids / Q000008:administration & dosage* / Q000235:genetics; D062085:RNA, Long Noncoding / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013552:Swine
chemical_list: D018398:Homeodomain Proteins; D050814:Octamer Transcription Factor-3; C494173:POU5F1 protein, human; D062085:RNA, Long Noncoding; C077885:XIST non-coding RNA