Progression of mouse oocytes from metaphase I to metaphase II is inhibited by fusion with G2 cells
Abstract
We show that in contrast to metaphase II oocytes, metaphase I oocytes cannot be activated by fusion with the zygote. Fusion of metaphase I oocytes with G2 zygotes was followed by premature chromosome condensation, with 60% of the hybrids becoming arrested at metaphase I, the remainder progressing and arresting at metaphase II. Hybrids of metaphase I oocytes and M-phase zygotes underwent accelerated maturation, but all arrested at metaphase II. In both cases the arrest could be overcome by treatment with the parthenogenetic activators ethanol and cycloheximide. We discuss these findings in relation to the possibility that the metaphase I oocyte contains cytostatic factor activity that is activated by its zygotic partner. Alternatively, the G2 zygote may provide an inhibitor of anaphase, normally never present in the metaphase I oocyte and which is absent from the M-phase zygote.
Additional Information
© 2000 Cambridge University Press. Date submitted: 25.11.99. Date accepted: 20.12.99. We are very grateful to Andrzej K. Tarkowski for support during the course of this work, for carefully reading this manuscript and for many useful comments. We thank Anna M. Ciemerych and David Glover for discussions and for all their help in writing the manuscript.Additional details
- Eprint ID
- 94854
- DOI
- 10.1017/s0967199400000927
- Resolver ID
- CaltechAUTHORS:20190422-101736181
- Created
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2019-04-23Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field