title: The effects of postovulatory aging of mouse oocytes on methylation and expression of imprinted genes at mid-term gestation.
abstract: Previous studies by others and ourselves have suggested that the methylation pattern of imprinted genes in oocytes is altered during postovulatory aging. The purpose of the current study was to evaluate the effects of postovulatory aging of mouse oocytes on methylation and expression of imprinted genes at the mid-gestation development stages. Proestrous females were artificially inseminated at 13 h (fresh-oocyte group) or 22 h (aged-oocyte group) post-hCG. Estrous females were mated with males as a control group. On dpc (day post coitus) 10.5 of development, embryos and placentas were collected and DNA and RNA were extracted, respectively. Methylation and total expression of Igf2r and H19 was investigated by quantitative analysis of methylation by PCR and quantitative real-time RT-PCR, respectively. Our results showed no significant changes of methylation in the differentially methylated region (DMR) and total expression of Igf2r in embryos and placentas, and no significant changes in methylation of H19 in embryos at dpc 10.5 of development compared with the control group regardless of artificial insemination of fresh or aged oocytes. In contrast, placentas of the aged-oocyte group exhibited significantly lower methylation levels in the H19 DMR. Furthermore, we observed that the increased expression of H19 in placentas of the aged-oocyte group was associated with significant hypomethylation of H19 DMR. These results suggest that postovulatory aging of mouse oocytes has adversed effects on methylation and expression of H19 in placentas at the mid-gestation development stage.
authors.affiliation: State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, #1 Beichen West Road, Chaoyang District, Beijing 100101, People's Republic of China.
authors.forename: Xing-Wei
authors.initials: XW
authors.lastname: Liang
authors.forename: Zhao-Jia
authors.initials: ZJ
authors.lastname: Ge
authors.forename: Liang
authors.initials: L
authors.lastname: Wei
authors.forename: Lei
authors.initials: L
authors.lastname: Guo
authors.forename: Zhi-Ming
authors.initials: ZM
authors.lastname: Han
authors.forename: Heide
authors.initials: H
authors.lastname: Schatten
authors.forename: Qing-Yuan
authors.initials: QY
authors.lastname: Sun
mesh_terms: D000818:Animals; D016922:Cellular Senescence / Q000235:genetics*; D019175:DNA Methylation; D004622:Embryo, Mammalian / Q000502:physiology; D005260:Female; D015870:Gene Expression; D018392:Genomic Imprinting; D005865:Gestational Age; D008297:Male; D051379:Mice; D009865:Oocytes / Q000166:cytology / Q000502:physiology*; D010920:Placenta / Q000502:physiology; D011247:Pregnancy; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism
chemical_list: C094335:H19 long non-coding RNA; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated