Meiotic induction by Xenopus cyclin B is accelerated by coexpression with mosXe. |
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| Authors: | R S Freeman S M Ballantyne and D J Donoghue |
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| Affiliation: | Department of Chemistry, University of California, San Diego, La Jolla 92093-0322. |
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| Abstract: | We have investigated the relationship between Xenopus laevis c-mos (mosXe) and the cyclin B component of maturation-promoting factor. Microinjection of Xenopus oocytes with in vitro-synthesized RNAs encoding Xenopus cyclin B1 or cyclin B2 induces the progression of meiosis, characterized by germinal vesicle breakdown (GVBD). By preinjecting oocytes with a mosXe-specific antisense oligonucleotide, we show that GVBD induced by cyclin B does not require expression of the mosXe protein. GVBD induced by cyclin B proceeds significantly faster than GVBD induced by progesterone or MosXe. However, coinjection of RNAs encoding cyclin B1 or cyclin B2 with mosXe RNA results in a 2.5- to 3-fold acceleration in GVBD relative to that induced by cyclin B alone. This acceleration of GVBD does not correlate with changes in the level of cyclin B1 and cyclin B2 phosphorylation. |
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