Dissociation of MAP kinase activation and MPF activation in hormone-stimulated maturation of Xenopus oocytes

Abstract

MAP kinase activation occurs during meiotic maturation of oocytes from all animals, but the requirement for MAP kinase activation in reinitiation of meiosis appears to vary between different classes. In particular, it has become accepted that MAP kinase activation is necessary for progesterone-stimulated meiotic maturation of Xenopus oocytes, while this is clearly not the case in other systems. In this paper, we demonstrate that MAP kinase activation in Xenopus oocytes is an early response to progesterone and can be temporally dissociated from MPF activation. We show that MAP kinase activation can be suppressed by treatment with geldanamycin or by overexpression of the MAP kinase phosphatase Pyst1. A transient and low-level early activation of MAP kinase increases the efficiency of cell cycle activation later on, when MAP kinase activity is no longer essential. Many oocytes can still undergo reinitiation of meiosis in the absence of active MAP kinase. Suppression of MAP kinase activation does not affect the formation or activation of Cdc2-cyclin B complexes, but reduces the level of active Cdc2 kinase. We discuss these findings in the context of a universal mechanism for meiotic maturation in oocytes throughout the animal kingdom.

Hsp90 is required for c-Mos activation and biphasic MAP kinase activation in Xenopus oocytes

“…We have recently reported that the specific Hsp90 inhibitor geldanamycin (GA) blocks sustained activation of MAP kinase in Xenopus oocytes (Fisher et al, 1999a), although we did not define the molecular target of Hsp90 inhibition. Mos translation is part of a positive feedback loop in which MAP kinase stimulates, and is apparently required for, Mos synthesis (Matten et al, 1996;Howard et al, 1999).…”

“…necessary for fertilization (Haccard et al, 1993;Colledge We have recently demonstrated that interference with the et al., 1994;Hashimoto et al, 1994). Mos is inactivated function of Hsp90 prevents activation of MAP kinase in after exit from meiosis (Lorca et al, 1991;Watanabe Xenopus oocyte maturation (Fisher et al, 1999a(Fisher et al, ), but how et al, 1991Roy et al, 1996) and this inactivation is prevention of MAP kinase activation is mediated was not required to allow entry into first mitosis (Abrieu et al, analysed. Here we show that Mos interacts with Hsp90 in 1997; Walter et al, 1997;Bitangcol et al, 1998; the oocyte and that this interaction is necessary for Mos et al, 1998) or, possibly, the first round of DNA activation, and thus for Mos-mediated MAP kinase activareplication in some species (Tachibana et al, 1997).…”

Antibody Microarray Analyses of Signal Transduction Protein Expression and Phosphorylation during Porcine Oocyte Maturation

“…Hormonal induction of meiotic maturation is first evident with the breakdown of the nuclear envelope (also known as germinal vesicle (GV) breakdown), and this is accompanied by a burst in total cellular protein phosphorylation catalyzed by a plethora of protein kinases. In one of the best characterized oocyte model systems, the African clawed frog Xenopus laevis oocyte, these kinases include Aurora, 6,7 CDK1, [10][11][12] CDK2, 13 CDK7/ MO15, 14 Chk2/Cds1, 15 casein kinase 2 (CK2), 16 ERK2, 9,12,[17][18][19][20][21][22] Haspin, 23,24 JNK, 25,26 MEK1, [27][28][29] MEK2, 30 Mos, 13,31,32 p38γ MAPK, 33 PKB/Akt, 34 Plx1, 35 Raf, [36][37][38][39][40] and RSK1 and RSK2. 9,20,38,[41][42][43] cAMP-dependent protein kinase (PKA) 34 and xPAK 44 are protein kinases that become inhibited during frog meiotic maturation.…”

“…Hormonal induction of meiotic maturation is first evident with the breakdown of the nuclear envelope (also known as germinal vesicle (GV) breakdown), and this is accompanied by a burst in total cellular protein phosphorylation catalyzed by a plethora of protein kinases. In one of the best characterized oocyte model systems, the African clawed frog Xenopus laevis oocyte, these kinases include Aurora, , CDK1, – CDK2, CDK7/MO15, Chk2/Cds1, casein kinase 2 (CK2), ERK2, ,,– Haspin, , JNK, , MEK1, – MEK2, Mos, ,, p38γ MAPK, PKB/Akt, Plx1, Raf, – and RSK1 and RSK2. ,,,– cAMP-dependent protein kinase (PKA) and xPAK are protein kinases that become inhibited during frog meiotic maturation. Many of these kinases and others (e.g., calmodulin-dependent kinase 2, phosphatidylinositol 3-kinase) are similarly regulated in other oocytes such as from the sea star, – clam, mouse, – rat, pig, – sheep, goat, and cow. ,,– In frog oocytes, severa...…”

Electrofusion Stimulation Is an Independent Factor of Chromosome Abnormality in Mice Oocytes Reconstructed via Spindle Transfer

“…With the increase in temperature or the extension of the high temperature, the spindle microtubules aggregation occurs, the spindle will also disappear but will not reappear after the temperature returns to normal, causing irreversible effects on oocytes (16)(17)(18). Besides, studies have shown that intracellular calcium oscillations triggered by sperm penetration during fertilization (19) and Ca 2+ influx induced by mechanical or chemical operation (20) can both lead to decreased kinase activity, activation of oocytes and recovery of meiosis (21). Thus, some study has speculated that ST manipulation in a Ca 2+ free medium may avoid spontaneous activation, but this has not been confirmed (3,22).…”