title: Maturation-promoting factor (MPF) is responsible for the transformation of sperm nuclei to metaphase chromosomes in maturing bovine oocytes in vitro.
abstract: Bovine oocytes at the germinal vesicle stage were inseminated in Brackett and Oliphant's medium in the presence of BSA (10 mg ml-1), caffeine (5 mmol l-1) and heparin (10 micrograms ml-1). When oocytes were transferred into tissue culture medium (TCM)-199 containing 10% fetal calf serum (FCS) with or without 6-dimethylaminopurine (6-DMAP; 2 mmol l-1) 8 h after insemination and cultured for 15-40 h at 39 degrees C in 5% CO2 in air, 74-83% of oocytes were penetrated and polyspermy (67-80%) was common. At 40 h after culture in 6-DMAP-free medium, 65% and 63% of unpenetrated and penetrated oocytes, respectively, reached metaphase II or beyond. A few (6%) oocytes were activated and contained both male and female pronuclei. Sperm metaphase chromosomes were observed in 90% of the penetrated oocytes. Penetration by more than four spermatozoa greatly retarded the meiotic maturation of the oocyte. However, sperm chromosomes were never observed in oocytes cultured in 6-DMAP supplemented medium and oocyte maturation did not proceed beyond the stage of prometaphase I. These results demonstrate the possible participation of maturation-promoting factor in metaphase chromosome formation in spermatozoa.
authors.affiliation: Department of Animal Science and Technology, Faculty of Agriculture, Okayama University, Japan.
authors.forename: L R
authors.initials: LR
authors.lastname: Abeydeera
authors.forename: K
authors.initials: K
authors.lastname: Niwa
authors.forename: K
authors.initials: K
authors.lastname: Okuda
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D002467:Cell Nucleus / Q000502:physiology; D002875:Chromosomes / Q000502:physiology*; D003470:Culture Media; D005260:Female; D005307:Fertilization in Vitro; D008297:Male; D016200:Maturation-Promoting Factor / Q000502:physiology*; D008677:Metaphase / Q000502:physiology; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D013094:Spermatozoa / Q000166:cytology / Q000502:physiology*; D013997:Time Factors
chemical_list: D003470:Culture Media; C001020:N(6),N(6)-dimethyladenine; D016200:Maturation-Promoting Factor; D000225:Adenine