title: In germ cells of mouse embryonic ovaries, the decision to enter meiosis precedes premeiotic DNA replication.
abstract: The transition from mitosis to meiosis is a defining juncture in the life cycle of sexually reproducing organisms. In yeast, the decision to enter meiosis is made before the single round of DNA replication that precedes the two meiotic divisions. We present genetic evidence of an analogous decision point in the germ line of a multicellular organism. The mouse Stra8 gene is expressed in germ cells of embryonic ovaries, where meiosis is initiated, but not in those of embryonic testes, where meiosis does not begin until after birth. Here we report that in female embryos lacking Stra8 gene function, the early, mitotic development of germ cells is normal, but these cells then fail to undergo premeiotic DNA replication, meiotic chromosome condensation, cohesion, synapsis and recombination. Combined with previous findings, these genetic data suggest that active differentiation of ovarian germ cells commences at a regulatory point upstream of premeiotic DNA replication.
authors.affiliation: Howard Hughes Medical Institute, Cambridge, Massachusetts 02142, USA.
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Baltus
authors.forename: Douglas B
authors.initials: DB
authors.lastname: Menke
authors.forename: Yueh-Chiang
authors.initials: YC
authors.lastname: Hu
authors.forename: Mary L
authors.initials: ML
authors.lastname: Goodheart
authors.forename: Anne E
authors.initials: AE
authors.lastname: Carpenter
authors.forename: Dirk G
authors.initials: DG
authors.lastname: de Rooij
authors.forename: David C
authors.initials: DC
authors.lastname: Page
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D004261:DNA Replication; D005260:Female; D008297:Male; D008540:Meiosis / Q000235:genetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009866:Oogenesis / Q000235:genetics; D010053:Ovary / Q000196:embryology* / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D013737:Testis / Q000196:embryology / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D011506:Proteins; C102019:Stra8 protein, mouse