title: Large-scale production of growing oocytes in vitro from neonatal mouse ovaries.
abstract: Although fetal or neonatal mammalian ovaries contain many non-growing oocytes within primordial follicles, most degenerate and only a few contribute to the oocyte pool in the mature ovary. Here, we report a follicle-free culture system that allows a large number of these arrested oocytes to enter the growth phase in vitro. As many as 800 oocytes from a newborn mouse, corresponding to more than 10(4) oocytes in large animals, continued to develop, formed a zona pellucida, and were able to fuse with spermatozoa. Some oocytes reached the size of those in normal antral follicles and entered metaphase I, indicating the completion of the growth phase. The key to success was the sequential provision of essential nutrients and growth factors to the oocytes, while preventing the apoptosis that normally occurs in the majority of growing oocytes in vivo. Importantly, maternal genomic imprinting, which is necessary for normal embryonic development, was imposed correctly on their genomes autonomously. Thus, arrested primordial oocytes can be rescued effectively in vitro and can undergo the morphological and genomic modifications necessary for fertilization and subsequent embryonic development. This culture system may provide a significant impetus to the development of new techniques for the efficient production of oocytes from fetal or neonatal ovaries, for research, clinical, and zoological purposes.
authors.affiliation: Bioresource Center, RIKEN, Tsukuba, Ibaraki 305-0074, Japan.
authors.forename: Arata
authors.initials: A
authors.lastname: Honda
authors.forename: Michiko
authors.initials: M
authors.lastname: Hirose
authors.forename: Kimiko
authors.initials: K
authors.lastname: Inoue
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Hiura
authors.forename: Hiromi
authors.initials: H
authors.lastname: Miki
authors.forename: Narumi
authors.initials: N
authors.lastname: Ogonuki
authors.forename: Michihiko
authors.initials: M
authors.lastname: Sugimoto
authors.forename: Kuniya
authors.initials: K
authors.lastname: Abe
authors.forename: Mito
authors.initials: M
authors.lastname: Kanatsu-Shinohara
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kono
authors.forename: Takashi
authors.initials: T
authors.lastname: Shinohara
authors.forename: Atsuo
authors.initials: A
authors.lastname: Ogura
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D018929:Cell Culture Techniques / Q000379:methods*; D049109:Cell Proliferation; D002478:Cells, Cultured; D005260:Female; D005786:Gene Expression Regulation; D008540:Meiosis; D008745:Methylation; D051379:Mice; D019319:Okadaic Acid / Q000494:pharmacology; D009865:Oocytes / Q000166:cytology* / Q000187:drug effects / Q000254:growth & development; D010053:Ovary / Q000166:cytology*; D013234:Stem Cells / Q000166:cytology
chemical_list: D019319:Okadaic Acid