title: Cell cycle arrest associated with anoxia-induced quiescence, anoxic preconditioning, and embryonic diapause in embryos of the annual killifish Austrofundulus limnaeus.
abstract: Embryos of the annual killifish Austrofundulus limnaeus can enter into dormancy associated with diapause and anoxia-induced quiescence. Dormant embryos are composed primarily of cells arrested in the G(1)/G(0) phase of the cell cycle based on flow cytometry analysis of DNA content. In fact, most cells in developing embryos contain only a diploid complement of DNA, with very few cells found in the S, G(2), or M phases of the cell cycle. Diapause II embryos appear to be in a G(0)-like state with low levels of cyclin D1 and p53. However, the active form of pAKT is high during diapause II. Exposure to anoxia causes an increase in cyclin D1 and p53 expression in diapause II embryos, suggesting a possible re-entry into the cell cycle. Post-diapause II embryos exposed to anoxia or anoxic preconditioning have stable levels of cyclin D1 and stable or reduced levels of p53. The amount of pAKT is severely reduced in 12 dpd embryos exposed to anoxia or anoxic preconditioning. This study is the first to evaluate cell cycle control in embryos of A. limnaeus during embryonic diapause and in response to anoxia and builds a foundation for future research on the role of cell cycle arrest in supporting vertebrate dormancy.
authors.affiliation: Department of Biology, Portland State University, P.O. Box 751, Portland, OR 97207-0751, USA.
authors.forename: Camie L
authors.initials: CL
authors.lastname: Meller
authors.forename: Robert
authors.initials: R
authors.lastname: Meller
authors.forename: Roger P
authors.initials: RP
authors.lastname: Simon
authors.forename: Kristin M
authors.initials: KM
authors.lastname: Culpepper
authors.forename: Jason E
authors.initials: JE
authors.lastname: Podrabsky
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western; D059447:Cell Cycle Checkpoints / Q000502:physiology*; D019938:Cyclin D1 / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000378:metabolism / Q000503:physiopathology*; D005434:Flow Cytometry; D000860:Hypoxia / Q000503:physiopathology*; D007695:Killifishes / Q000196:embryology* / Q000378:metabolism; D051058:Oncogene Protein v-akt / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D016159:Tumor Suppressor Protein p53; D019938:Cyclin D1; D051058:Oncogene Protein v-akt