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XB-ART-5756
Mol Cell Biol 2003 Mar 01;235:1703-16. doi: 10.1128/MCB.23.5.1703-1716.2003.
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Biphasic activation of Aurora-A kinase during the meiosis I- meiosis II transition in Xenopus oocytes.

Ma C , Cummings C , Liu XJ .


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Xenopus Aurora-A (also known as Eg2) is a member of the Aurora family of mitotic serine/threonine kinases. In Xenopus oocytes, Aurora-A phosphorylates and activates a cytoplasmic mRNA polyadenylation factor (CPEB) and therefore plays a pivotal role in MOS translation. However, hyperphosphorylation and activation of Aurora-A appear to be dependent on maturation-promoting factor (MPF) activation. To resolve this apparent paradox, we generated a constitutively activated Aurora-A by engineering a myristylation signal at its N terminus. Injection of Myr-Aurora-A mRNA induced germinal vesicle breakdown (GVBD) with the concomitant activation of MOS, mitogen-activated protein kinase, and MPF. Myr-Aurora-A-injected oocytes, however, appeared to arrest in meiosis I with high MPF activity and highly condensed, metaphase-like chromosomes but no organized microtubule spindles. No degradation of CPEB or cyclin B2 was observed following GVBD in Myr-Aurora-A-injected oocytes. In the presence of progesterone, the endogenous Aurora-A became hyperphosphorylated and activated at the time of MPF activation. Following GVBD, Aurora-A was gradually dephosphorylated and inactivated before it was hyperphosphorylated and activated again. This biphasic pattern of Aurora-A activation mirrored that of MPF activation and hence may explain meiosis I arrest by the constitutively activated Myr-Aurora-A.

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Species referenced: Xenopus
Genes referenced: aurka cpeb1 mos

References [+] :
Andrésson, The kinase Eg2 is a component of the Xenopus oocyte progesterone-activated signaling pathway. 1998, Pubmed, Xenbase