title: Phenotypes of Aging Postovulatory Oocytes After Somatic Cell Nuclear Transfer in Mice.
abstract: Oocytes rapidly lose their developmental potential after ovulation, termed postovulatory oocyte aging, and often exhibit characteristic phenotypes, such as cytofragmentation, abnormal spindle shapes, and chromosome misalignments. Here, we reconstructed mouse oocytes using somatic cell nuclear transfer (SCNT) to reveal the effect of somatic cell-derived nuclei on oocyte physiology during aging. Normal oocytes started undergoing cytofragmentation 24 hours after oocyte collection; however, this occurred earlier in SCNT oocytes and was more severe at 48 hours, suggesting that the transferred somatic cell nuclei affected oocyte physiology. We found no difference in the status of acetylated α-tubulin (Ac-Tub) and α-tubulin (Tub) between normal and SCNT aging oocytes, but unlike normal oocytes, aging SCNT oocytes did not have astral microtubules. Interestingly, aging SCNT oocytes displayed more severely scattered chromosomes or irregularly shaped spindles. Observations of the microfilaments showed that, in normal oocytes, there was a clear actin ring beneath the plasma membrane and condensed microfilaments around the spindle (the actin cap) at 0 hours, and the actin filaments started degenerating at 1 hour, becoming completely disrupted and distributed to the cytoplasm at 24 hours. By contrast, in SCNT oocytes, an actin cap formed around the transplanted nuclei within 1 hour of SCNT, which was still present at 24 hours. Thus, SCNT oocytes age in a similar but distinct way, suggesting that they not only contain nuclei with abnormal epigenetics but are also physiologically different.
authors.affiliation: 1 Graduate School of Biology-Oriented Science and Technology, Kinki University , Wakayama, Japan .
authors.forename: Ah Reum
authors.initials: AR
authors.lastname: Lee
authors.affiliation: 2 Department of Virology II, National Institute of Infectious Diseases , Tokyo, Japan .
authors.forename: Takashi
authors.initials: T
authors.lastname: Shimoike
authors.affiliation: 3 Faculty of Life and Environmental Sciences, University of Yamanashi , Yamanashi, Japan .|4 Advanced Biotechnology Center, University of Yamanashi , Kofu-shi, Japan .
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Wakayama
authors.affiliation: 1 Graduate School of Biology-Oriented Science and Technology, Kinki University , Wakayama, Japan .|3 Faculty of Life and Environmental Sciences, University of Yamanashi , Yamanashi, Japan .|5 PRESTO, Japan Science and Technology Agency , Saitama, Japan .
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kishigami
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D016922:Cellular Senescence / Q000502:physiology*; D002875:Chromosomes; D003593:Cytoplasm / Q000378:metabolism; D005260:Female; D051379:Mice; D053652:Nuclear Transfer Techniques; D009865:Oocytes / Q000166:cytology*; D010641:Phenotype; D014404:Tubulin / Q000378:metabolism*
chemical_list: D014404:Tubulin