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Mouse Mos protooncogene product is present and functions during oogenesis
R S Paules1, R Buccione, R C Moschel
1BRI-Basic Research Program, National Cancer Institute-Frederick Cancer Research Facility, MD 21701.
Abstract:
We have identified the mouse Mos-encoded protein product, p39mos, in maturing mouse oocytes and have shown that it is indistinguishable from the product expressed in Mos-transformed NIH 3T3 cells. p39mos is detected in oocytes arrested in the first meiotic prophase, during germinal-vesicle breakdown, metaphase I, anaphase I, and in ovulated eggs. We show that microinjection of three different Mos antisense (but not sense) oligodeoxyribonucleotides into germinal vesicle-stage oocytes prevents first polar-body emission and therefore interrupted the normal progression of meiosis. These results show that in mouse oocytes, as in the amphibian Xenopus [Sagata, N., Oskarsson, M., Copeland, T., Brumbaugh, J. & Vande Woude, G.F. (1988) Nature (London) 335, 519-525], the product of Mos is necessary for normal meiotic maturation.
Insights
The mouse Mos protein (p39mos) is crucial for oocyte maturation. Inhibiting Mos with antisense oligodeoxynucleotides blocks meiotic progression in mouse oocytes.
Area of Science:
- Molecular Biology
- Developmental Biology
- Cell Biology
Background:
- The Mos-encoded protein (p39mos) is involved in cellular transformation.
- Its role in mammalian oocyte maturation was previously unclear.
Purpose of the Study:
- To identify and characterize the mouse Mos protein in oocytes.
- To determine the necessity of Mos for meiotic maturation in mouse oocytes.
Main Methods:
- Western blot analysis to detect p39mos in mouse oocytes.
- Microinjection of antisense and sense oligodeoxynucleotides into oocytes.
- Observation of meiotic progression and polar body emission.
Main Results:
- p39mos was identified in mouse oocytes at various meiotic stages, including metaphase I and ovulated eggs.
- Microinjection of Mos antisense oligodeoxynucleotides, but not sense ones, inhibited the first polar body emission.
- Meiotic progression was interrupted in oocytes treated with Mos antisense oligodeoxynucleotides.
Conclusions:
- The Mos protein product is essential for normal meiotic maturation in mouse oocytes.
- These findings support a conserved role for Mos in oocyte maturation across species, similar to Xenopus.