Reducing PIP2 hydrolysis, Ins(1,4,5)P-3 receptor availability, or calcium gradients inhibits progesterone-stimulated Xenopus oocyte maturation
- Author(s)
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Han, JK, Lee, Sung Kuk
- Issued Date
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1995-03
- DOI
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10.1006/bbrc.1995.2860
- URI
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https://scholarworks.unist.ac.kr/handle/201301/6789
- Fulltext
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http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=0029417187
- Citation
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BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, v.217, no.3, pp.931 - 939
- Abstract
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In this report, we investigated the possibility that a product of phosphatidylinositol 4,5-bisphosphate (PIP2) breakdown, inositol 1,4,5-trisphosphate (Ins(1,4,5)P-3), and its downstream effector, Ca2+, is involved in oocyte maturation. Microinjection of monoclonal antibody specifically directed to PIP2 into oocytes prior to progesterone addition inhibited meiotic maturation. In addition, preventing or suppressing the progesterone-induced increase in [Ca2+](i) and maintaining cytosolic free Ca2+ of oocyte at 0.1 or 0.3 mu M by Br-2-BAPTA buffered Ca2+ solutions, completely blocked maturation. However, raising cytosolic Ca2+ concentration of oocyte to 1.0 or 3.0 mu M, the inhibitory Br-2-BAPTA effects on oocyte maturation was greatly diminished. Finally, microinjection of heparin, a potent antagonist of Ins(1,4,5)P-3 receptor, inhibited progesterone-induced oocyte maturation in a manner that is linearly proportional to its cytoplasmic concentration. These results strongly support the hypothesis that PIP2 turnover as well as Ins(1,4,5)P-3-induced Ca2+ release play crucial roles in regulating normal meiotic cell division in Xenopus oocyte.
- Publisher
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ACADEMIC PRESS INC ELSEVIER SCIENCE
- ISSN
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0006-291X
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