title: High developmental competence of pig oocytes after meiotic inhibition with a specific M-phase promoting factor kinase inhibitor, butyrolactone I.
abstract: Butyrolactone I specifically inhibits M-phase promoting factor activation and prevents the resumption of meiosis. These experiments were conducted to examine effects of butyrolactone I on pig oocytes in a serum-free maturation system. The first experiment was conducted to determine the effect of butyrolactone I (0-100 microM) on nuclear maturation. At concentrations of > or =12.5 microM, germinal vesicle breakdown was prevented in >90% of the oocytes after 24 h of culture. In the second experiment, the kinetics of in vitro maturation of butyrolactone I-treated oocytes was investigated. Oocytes were treated with 0 or 12.5 microM butyrolactone I and FSH for 20 h and then cultured with LH in the absence of butyrolactone I for another 24 h. Fewer butyrolactone I-treated oocytes reached MII stage at 36 h compared with controls (5.8% vs. 62.4%, P < 0.01). However, by 44 h, 83.4% of butyrolactone I-treated oocytes reached MII compared with 88.6% of controls. In the third experiment, butyrolactone I-treated oocytes were fertilized and cultured in vitro. No differences (P > 0.05) were found between controls and treated groups in cleavage rate, blastocyst rate, or mean number of cells per blastocyst. Effects of butyrolactone I on mitogen-activated protein kinase activation and localization of microfilaments and active mitochondria were examined by Western blot analysis and laser scanning confocal microscopy, respectively. The results suggested that although butyrolactone I reversibly inhibited germinal vesicle breakdown and mitogen-activated protein kinase activation, it did not affect mitochondrial and microfilament dynamics. Butyrolactone I is a potent inhibitor of nuclear maturation of porcine oocytes, and the inhibition is fully reversible.
authors.affiliation: Department of Animal Sciences, University of Missouri-Columbia, Columbia, MO 65211, USA.
authors.forename: Guang-Ming
authors.initials: GM
authors.lastname: Wu
authors.forename: Qing-Yuan
authors.initials: QY
authors.lastname: Sun
authors.forename: Jiude
authors.initials: J
authors.lastname: Mao
authors.forename: Liangxue
authors.initials: L
authors.lastname: Lai
authors.forename: Tod C
authors.initials: TC
authors.lastname: McCauley
authors.forename: Kwang-Wook
authors.initials: KW
authors.lastname: Park
authors.forename: Randall S
authors.initials: RS
authors.lastname: Prather
authors.forename: Brad A
authors.initials: BA
authors.lastname: Didion
authors.forename: Billy N
authors.initials: BN
authors.lastname: Day
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000494:pharmacology*; D008841:Actin Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D000818:Animals; D002467:Cell Nucleus / Q000502:physiology / Q000648:ultrastructure; D002843:Chromatin / Q000378:metabolism / Q000648:ultrastructure; D003593:Cytoplasm / Q000502:physiology / Q000648:ultrastructure; D005314:Embryonic and Fetal Development / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D005307:Fertilization in Vitro / Q000187:drug effects; D016200:Maturation-Promoting Factor / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008540:Meiosis / Q000187:drug effects*; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000378:metabolism / Q000648:ultrastructure; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009865:Oocytes / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D010766:Phosphorylation; D013552:Swine
chemical_list: D002843:Chromatin; D004791:Enzyme Inhibitors; C082868:butyrolactone I; D016200:Maturation-Promoting Factor; D020928:Mitogen-Activated Protein Kinases; D015107:4-Butyrolactone