title: Contribution of spermatozoal centrosomes to the microtubule-organizing centre in Antarctic minke whale ( Balaenoptera bonaerensis ).
abstract: Using an interspecies microinsemination assay with bovine oocytes, it was examined whether centrosomes of Antarctic minke whale spermatozoa function as the microtubule-organizing centre (MTOC). Bull and rat spermatozoa were used as positive and negative controls, respectively. Vitrified-warmed bovine mature oocytes were subjected to immunostaining against alpha-tubulin 4-6 h after intracytoplasmic injection (ICSI) of 5 mM dithiothreitol-treated spermatozoa. Aster formation occurred from whale spermatozoa (33%) and bull spermatozoa (33%), but very little from rat spermatozoa (3%). Activation treatment for the microinseminated oocytes with 7% ethanol + 2 mM 6-dimethylaminopurine resulted in a similar proportion of oocytes forming a whale sperm aster (35% vs 27% in the non-treated group; 4 h after ICSI) but a significantly larger aster (ratio of aster diameter to oocyte diameter, 0.57 vs 0.30 in the non-treated group). These results indicate that the centrosome introduced into bovine oocytes by whale spermatozoa contributes to the MTOC and that assembly of the microtubule network is promoted by oocyte activation.
authors.affiliation: Faculty of Textile Science and Technology, Shinshu University, Ueda, Nagano 386-8567, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Kazue
authors.initials: K
authors.lastname: Amemiya
authors.forename: Kana
authors.initials: K
authors.lastname: Takeuchi
authors.forename: Tomomi
authors.initials: T
authors.lastname: Tsujioka
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Tominaga
authors.forename: Masumi
authors.initials: M
authors.lastname: Hirabayashi
authors.forename: Hajime
authors.initials: H
authors.lastname: Ishikawa
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Fukui
authors.forename: Shinichi
authors.initials: S
authors.lastname: Hochi
mesh_terms: D000818:Animals; D000864:Antarctic Regions; D002417:Cattle; D018385:Centrosome / Q000502:physiology*; D008297:Male; D022101:Microtubule-Organizing Center / Q000502:physiology*; D051381:Rats; D013045:Species Specificity; D020554:Sperm Injections, Intracytoplasmic; D013094:Spermatozoa / Q000502:physiology*; D014404:Tubulin / Q000502:physiology; D014907:Whales / Q000502:physiology*
chemical_list: D014404:Tubulin