Inactivation of MPF and MAP kinase by single electrical stimulus for parthenogenetic development of porcine oocytes.
This study was conducted to examine the activities of maturation-promoting factor (MPF) and mitogen-activated protein (MAP) kinase in the porcine oocytes after artificial activation. To determine optimal electrical activation condition, oocytes were exposed to single DC pulse in a variety of electric field strengths (120, 150, 180, and 210 V/mm) and pulse durations (15, 30, 45, and 60 microsec). After the artificial activation, 40-50 oocytes were cultured in a 50 microl drop of NCSU23 medium supplemented with 0.4% BSA at 39 degrees C, 5% CO2 in air for 6 days. No difference was detected in the preimplantation development of pocine oocytes and the mean nuclei number of blastocysts between electric field strengths. Under the 180 V/mm electric field strength, short pulse durations (15 and 30 microsec) showed a higher preimplantation developmental rate of the oocytes and mean nuclei number of blastocysts than an extended electric pulse (60 microsec) (P < 0.05). Single electrical stimulus (180 V/mm, 15 microsec) resulted in higher preimplantation development of porcine oocytes as compared to other chemical stimulators (P < 0.01). Western blot analyses showed the decrease of MPF and MAP kinase in the electrically-activated oocytes. After single electrical stimulus, the amounts of both cdc2 and ERK in porcine oocytes were remarkably reduced by 4 hr and then further decreased by 8 hr. However, the chemically-stimulated oocytes did not show any significant change at the levels of MPF and MAP kinase. Our results indicate that the optimal single electrical pulse is effective on the inactivation of MPF and MAP kinase, eventually leading to the parthenogenetic development of porcine oocytes.
Koo
Deog-Bon
DB
Laboratory of Development and Differentiation, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea.
Chae
Jung-Il
JI
Kim
Ji-Su
JS
Wee
Gabbine
G
Song
Bong-Seok
BS
Lee
Kyung-Kwang
KK
Han
Yong-Mahn
YM
D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D004558:Electric Stimulation / Q000379:methods; D004624:Embryo Transfer; D004789:Enzyme Activation; D005260:Female; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009865:Oocytes / Q000166:cytology / Q000201:enzymology*; D010312:Parthenogenesis; D013552:Swine
D016203:CDC2 Protein Kinase; D020928:Mitogen-Activated Protein Kinases