title: Overexpression of OCT4A ortholog elevates endogenous XIST in porcine parthenogenic blastocysts.
abstract: X-chromosome inactivation (XCI) is an epigenetic process that equalizes expression of X-borne genes between male and female eutherians. This process is observed in early eutherian embryo development in a species-specific manner. Until recently, various pluripotent factors have been suggested to regulate the process of XCI by repressing XIST expression, which is the master inducer for XCI. Recent insights into the process and its regulation have been restricted in mouse species despite the evolutionary diversity of the process and molecular mechanism among the species. OCT4A is one of the represented pluripotent factors, the gate-keeper for maintaining pluripotency, and an XIST repressor. Therefore, in here, we examined the relation between OCT4A and X-linked genes in porcine preimplantation embryos. Three X-linked genes, XIST, LOC102165544, and RLIM, were selected in present study because their orthologues have been known to regulate XCI in mice. Expression levels of OCT4A were positively correlated with XIST and LOC102165544 in female blastocysts. Furthermore, overexpression of exogenous human OCT4A in cleaved parthenotes generated blastocysts with increased XIST expression levels. However, increased XIST expression was not observed when exogenous OCT4A was obtained from early blastocysts. These results suggest the possibility that OCT4A would be directly or indirectly involved in XIST expression in earlier stage porcine embryos rather than blastocysts.
authors.affiliation: Department of Agricultural Biotechnology, Animal Biotechnology Major, and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Republic of Korea.
authors.forename: Jae Yeon
authors.initials: JY
authors.lastname: Hwang
authors.forename: Kwang-Hwan
authors.initials: KH
authors.lastname: Choi
authors.forename: Dong-Kyung
authors.initials: DK
authors.lastname: Lee
authors.forename: Seung-Hun
authors.initials: SH
authors.lastname: Kim
authors.forename: Eun Bae
authors.initials: EB
authors.lastname: Kim
authors.forename: Sang-Hwan
authors.initials: SH
authors.lastname: Hyun
authors.forename: Chang-Kyu
authors.initials: CK
authors.lastname: Lee
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000502:physiology*; D005260:Female; D018014:Gene Transfer Techniques; D050172:Genes, X-Linked; D006801:Humans; D016086:Lentivirus; D008297:Male; D051379:Mice; D050810:Octamer Transcription Factors / Q000502:physiology*; D010312:Parthenogenesis / Q000502:physiology*; D060888:Real-Time Polymerase Chain Reaction; D013552:Swine; D014960:X Chromosome / Q000235:genetics*; D049951:X Chromosome Inactivation / Q000502:physiology*
chemical_list: D050810:Octamer Transcription Factors