title: Maternal gamma (gamma)-tubulin is involved in microtubule reorganization during bovine fertilization and parthenogenesis.
abstract: In this study, gamma-tubulin distribution was determined chronologically in conjunction with microtubule dynamics during bovine fertilization and parthenogenesis. In unfertilized bovine oocytes, gamma-tubulin was identified in the cytoplasm, mainly in the cortex and concentrated in the meiotic spindle. Following sperm penetration, gamma-tubulin in the cytoplasm was recruited by a sperm component. During pronuclear apposition, gamma-tubulin was localized as spots at the spindle poles. gamma-tubulin spots were observed in blastomeres of embryos cleaved in vitro. Following electrical stimulation, gamma-tubulin and microtubule matrix were noted in oocyte cortex. In the late pronuclear stage, considerably less gamma-tubulin and microtubules were detected in the cytoplasm. At the mitotic metaphase of parthenotes, gamma-tubulin was recruited to the condensed chromatin and concentrated in the spindle. The gamma-tubulin spots were not detected until the 8-cell stage of parthenotes. This suggests that maternal gamma-tubulin is recruited by a sperm component to reconstitute the zygotic centrosome. In the absence of sperm components, the cell cycle-related assembly of gamma-tubulin organizes microtubule nucleation for positioning the pronucleus and spindle protein of mitotic metaphase during the first cell cycle of bovine parthenotes.
authors.affiliation: Department of Animal Sciences, Chungbuk National University, Cheong Ju, Chungbuk, Korea.
authors.forename: Mi-Ra
authors.initials: MR
authors.lastname: Shin
authors.forename: Nam-Hyung
authors.initials: NH
authors.lastname: Kim
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002417:Cattle; D018385:Centrosome / Q000378:metabolism; D005306:Fertilization / Q000502:physiology*; D018613:Microscopy, Confocal; D008870:Microtubules / Q000378:metabolism*; D010312:Parthenogenesis / Q000502:physiology*; D013997:Time Factors; D014404:Tubulin / Q000378:metabolism*; D015053:Zygote / Q000378:metabolism
chemical_list: D014404:Tubulin