Oscillation of inositol polyphosphates in the embryonic cleavage cycle of the Xenopus laevis.
Evidence suggests that a transient increase in intracellular calcium ([Ca2+]i) is an important modulator during the cell division cycle in early embryos. We have recently shown that inhibition of Ins(1,4,5)P3-induced Ca2+ release in the cleaving Xenopus embryos greatly lengthens the cell cycle duration. In this report, we have directly measured the changes of Ins(1,4,5)P3 content during the first two cleavage cycles in the Xenopus embryos. HPLC profiles of cell extracts from dividing embryos show oscillations of inositol polyphosphates throughout the cleavage cycle with a transient production of Ins(1,4,5)P3 by the time of cleavage furrow completion. In addition, cyclic changes in inositol phospholipids, phosphatidylinositol 4,5-bisphosphate (PIP2) and phosphatidylinositol 4-phosphate (PIP) were detected during the cleavage cycle. These data strongly suggest the involvement of PIP2 turnover and periodic increase in Ins(1,4,5)P3 triggers [Ca2+]i transients during the early embryonic cell cycle in the Xenopus.
Han
J K
JK
Department of Life Sciences, Pohang University of Science and Technology, South Korea.
D000818:Animals; D002453:Cell Cycle; D002855:Chromatography, Thin Layer; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000502:physiology*; D005260:Female; D007294:Inositol / Q000378:metabolism; D007295:Inositol Phosphates / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D009865:Oocytes / Q000166:cytology / Q000502:physiology*; D009991:Oscillometry; D010716:Phosphatidylinositols / Q000302:isolation & purification / Q000378:metabolism; D014982:Xenopus laevis / Q000196:embryology
D007295:Inositol Phosphates; D010716:Phosphatidylinositols; D007294:Inositol