title: Maternal-effect gene Ces5/Ooep/Moep19/Floped is essential for oocyte cytoplasmic lattice formation and embryonic development at the maternal-zygotic stage transition.
abstract: In a search for genes specifically expressed in mouse embryonic stem cells, we identified one we called Ces5. We found that it corresponded to the Ooep gene, which was recently reported to be expressed specifically in oocytes. Mouse Ces5/Ooep, also called Moep19 or Floped, encoded a 164-amino acid protein, which was detected in the cytoplasm of developing and mature oocytes and in embryos throughout the preimplantation period. To examine its function, we carried out targeted disruption of this gene. The Ces5/Ooep-null mice were grossly normal, but the females were infertile. Although the ovaries and ovulation appeared normal, the embryos from Ces5/Ooep-null females mated with wild-type males showed developmental arrest at the two- or four-cell stage. In addition, their first cleavage was considerably delayed and often asymmetrical. Thus, Ces5/Ooep is a maternal-effect gene. By electron microscopy, we found that the eggs from Ces5/Ooep-null females lacked oocyte cytoplasmic lattices (CPLs), which have long been predicted to function as a storage form for components that are maternally contributed to the early embryo. Further analysis showed that CES5/OOEP was directly associated with the CPLs. These results indicate that CES5/OOEP is an essential component of the CPLs and is required for embryonic development at the maternal-zygotic stage transition.
authors.affiliation: Division of Stem Cell Regulation Research, G6, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Fumi
authors.initials: F
authors.lastname: Tashiro
authors.forename: Masami
authors.initials: M
authors.lastname: Kanai-Azuma
authors.forename: Satsuki
authors.initials: S
authors.lastname: Miyazaki
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kato
authors.forename: Tomofumi
authors.initials: T
authors.lastname: Tanaka
authors.forename: Shuichi
authors.initials: S
authors.lastname: Toyoda
authors.forename: Eiji
authors.initials: E
authors.lastname: Yamato
authors.forename: Hayato
authors.initials: H
authors.lastname: Kawakami
authors.forename: Tatsushi
authors.initials: T
authors.lastname: Miyazaki
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Miyazaki
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003593:Cytoplasm / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000196:embryology* / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009865:Oocytes / Q000166:cytology* / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics; D015053:Zygote / Q000166:cytology / Q000378:metabolism*
chemical_list: C527277:MOEP19 protein, mouse; D012333:RNA, Messenger; D016601:RNA-Binding Proteins