Maintenance of meiotic arrest in bovine oocytes in vitro using butyrolactone I: effects on oocyte ultrastructure and nucleolus function.
In this study, we have shown that butyrolactone I (BL-I), a potent inhibitor of cyclin-dependent kinases, affects oocyte cytoplasmic morphology and nuclear function in terms of nucleolar ultrastructure and immunocytochemistry. Bovine oocytes were recovered from three classes of follicle size: 1.5-2, 2-3, and 3-6 mm. The oocytes were incubated for 40 hr with BL-I, and subsequently processed for transmission electron microscopy or immunocytochemistry. A control group of oocytes were processed immediately upon recovery (0 hr). In general, incubation with BL-I for 40 hr disrupted contact between cells of the cumulus oophorous and the oocyte, caused degeneration of the cortical granules and the peripheral migration of all cytoplasmic organelles. At the level of the nucleus, it induced convolution of the nuclear membrane and caused acceleration of nucleolar compaction in oocytes from follicles < 3 mm and fragmentation of nucleoli, particularly evidenced by immunocytochemistry, in oocytes from follicles > 3 mm. Furthermore, the effects appear to be more profound in fully-grown oocytes.
Department of Animal Science and Production and The Conway Institute for Biomedical and Biomolecular Research, University College Dublin, Lyons Research Farm, Newcastle, County Dublin, Ireland. trudee.fair@ucd.ie
Trudee
T
Fair
Poul
P
Hyttel
Jan
J
Motlik
Maurice
M
Boland
Patrick
P
Lonergan
D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000818:Animals; D002417:Cattle; D002466:Cell Nucleolus / Q000187:drug effects / Q000502:physiology; D048429:Cell Size; D005260:Female; D066298:In Vitro Techniques; D008540:Meiosis / Q000187:drug effects*; D009687:Nuclear Proteins / Q000378:metabolism; D009865:Oocytes / Q000166:cytology / Q000187:drug effects* / Q000648:ultrastructure; D006080:Ovarian Follicle / Q000166:cytology; D047428:Protein Kinase Inhibitors
D009687:Nuclear Proteins; D047428:Protein Kinase Inhibitors; C082868:butyrolactone I; D015107:4-Butyrolactone