A rise in cytosolic calcium is not necessary for maturation of Xenopus laevis oocytes

Cork, R. J.; Cicirelli, Michael F.; Robinson, K. R.

doi:10.1016/0012-1606(87)90136-9

Cited by 58 publications

(32 citation statements)

References 25 publications

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“…Half the oocytes were then treated continuously with 10 µg/ml progesterone, whilst the other half were treated with the equivalent 111 However, in amphibian oocytes the extent and necessity of the increase in intracellular Ca 2+ have been questioned (Robinson 1985;Cork et al 1987). These studies reported the absence of a consistent intracellular Ca 2+ release during oocyte maturation and are in apparent conflict with the studies that indicate a positive role for Ca 2+ in oocyte maturation.…”

Section: Kinetic Analysis Of 45 Ca 2+ Mobilizationmentioning

confidence: 92%

The role of Ca 2+ in progesterone-induced germinal vesicle breakdown of Xenopus laevis oocytes: the synergic effects of microtubule depolymerization and Ca 2+

Duesbery

Masui

1996

Development Genes and Evolution

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By monitoring (45)Ca(2+) influx and efflux from oocytes a transient increase followed by a transient decrease in the Ca(2+)-content of progesterone-treated oocytes was observed. Chelation of intracellular Ca(2+) with EGTA or BAPTA-type buffers inhibited progesterone-induced GVBD. Buffers with a mid-range Kd (∼1.5 μM) were most effective in inhibiting GVBD whereas buffers with a Kd above or below this value were less effective. These observations indicate that intracellular Ca(2+), probably in the form of a localized release, is required for progesterone-induced oocyte maturation. However, Ca(2+) alone was insufficient to induce GVBD. When the effects of nocodazole and taxol upon this Ca(2+)-requirement were tested, we observed that taxol-induced microtubule polymerization not only delayed progesterone-induced GVBD but also completely inhibited it in combination with BAPTA-AM. Conversely, nocodazole-induced microtubule depolymerization in combination with ionophore A23187 not only accelerated progesterone-induced GVBD, but also induced GVBD in the absence of progesterone. The combined treatment of oocytes with nocodazole and InsP3, or with cold treatment and ionophore A23187 also induced GVBD in the absence of progesterone. Thus, Ca(2+) and microtubule depolymerization synergistically promote GVBD. In both nocodazole- and cold-treated oocytes, the GV was displaced to the periphery of the oocyte and underwent GVBD when treated with A23187. However, when the GV was displaced to the cortex by a centrifugal force under conditions that would not cause microtubule depolymerization and the oocyte was treated with A23187, oocytes did not undergo GVBD.

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Section: Kinetic Analysis Of 45 Ca 2+ Mobilizationmentioning

confidence: 92%

The role of Ca 2+ in progesterone-induced germinal vesicle breakdown of Xenopus laevis oocytes: the synergic effects of microtubule depolymerization and Ca 2+

Duesbery

Masui

1996

Development Genes and Evolution

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“…In the oocyte, however, the function of Ca2+ mobilizing receptors remains unclear. The maturation of the oocyte induced by progesterone is reported not to depend on an increase in cytosolic Ca2' (11) Fig. 7B.…”

Section: Discussionmentioning

confidence: 99%

“…A comparison was made of the responsiveness between voltage clamping and fura-2 detectable Ca2+ changes. Oocytes were tested in groups of five by electrophysiology and imaging and both gave responses at doses of 0.01, 0.1, and 1 ,uM substance K. iological and imaging responses were also observed in uninjected oocytes stimulated with agonists for endogenous receptors that are coupled to inositol phospholipid hydrolysis with mobilization of intracellular Ca2l (11). In noninjected oocytes from some toad oocyte donors, 100 ,M carbachol (Fig.…”

mentioning

confidence: 99%

Calcium wave evoked by activation of endogenous or exogenously expressed receptors in Xenopus oocytes.

Brooker

Seki

Croll

et al. 1990

Proc. Natl. Acad. Sci. U.S.A.

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“…3). The effect of progesterone treatment on X. laevis oocytes has been widely investigated [11,26,27], but nevertheless the mechanism of action of this hormone in X. laevis oocytes is still not fully understood. It is accepted, however, that progesterone-induced GVBD follows a different pattern from that induced by ras-p21 [28].…”

Section: Effects Of Acylphosphatase Injection On Ras-p21 and Progestementioning

confidence: 99%

Microinjection of acylphosphatase blocks Xenopus laevis oocytes maturation induced by ras‐p21

et al. 1993

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ras proteins induce germinal vesicle breakdown (GVBD) when microinjected into Xenopus laevis oocytes. The mechanism of action is still unresolved, although several hypotheses have been proposed. Acylphosphatase is a cytosolic enzyme that specifically catalyses the hydrolysis of the carboxylphosphate bond of acylphosphate for the removal of acylphosphate residues of various membrane pumps. A direct effect of acylphosphatase on the regulation of ionic balance of a cell by interaction with ionic membrane pumps has been proposed. We have analyzed the effect of microinjecting acylphosphatase, by itself or along with ras-p21 proteins or progesterone, into oocytes. The enzyme alone is unable to induce GVBD, but increases oocyte maturation induced by progesterone. By contrast, acylphosphatase blocked GVBD induced by microinjection of oncogenic ras-p21. These data suggest that acylphosphatase acts synergistically or antagonistically with factors involved in proliferating signals by altering the intracellular ionic conditions of the cell, conforming the hypothesis that the intracellular ionic condition of the cell is important in the induction of proliferating signals, and that its perturbation may have a serious effect on signal transduction.

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A rise in cytosolic calcium is not necessary for maturation of Xenopus laevis oocytes

Cited by 58 publications

References 25 publications

The role of Ca 2+ in progesterone-induced germinal vesicle breakdown of Xenopus laevis oocytes: the synergic effects of microtubule depolymerization and Ca 2+

The role of Ca 2+ in progesterone-induced germinal vesicle breakdown of Xenopus laevis oocytes: the synergic effects of microtubule depolymerization and Ca 2+

Calcium wave evoked by activation of endogenous or exogenously expressed receptors in Xenopus oocytes.

Microinjection of acylphosphatase blocks Xenopus laevis oocytes maturation induced by ras‐p21

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