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Mouse Oocyte Microinjection, Maturation and Ploidy Assessment
Published on: July 23, 2011
Effect of phorbol ester PMA and puromycin on the maturation of mouse oocytes
1Laboratory of Experimental Embryology, Medical Academy, Warsaw, Poland.
Abstract:
The effect of phorbol myristate acetate (PMA) and puromycin (PU) on maturation divisions of mouse oocytes was investigated. PMA changed the morphology and function of the spindle in meiosis I. The spindle had a broad polar region and did not commence karyokinesis in the first maturation division. This persisted in 25% of spindles which were passive up to 30 h of maturation. Half of the oocytes with spindles blocked by PMA between 20 and 30 h of maturation became activated, and 25% of the initial pool underwent abortive karyokinesis consisting of segregation of several chromosomes of the metaphase plate. Cytological observation indicated that the presence of PMA interfered with the elongation of the spindle in anaphase. Under the condition of changed phosphorylation of maturation of proteins by PMA, a reversible interphase was induced by PU. Most of the nuclei induced by PU exhibited pronuclei. A new class of nuclei induced by PU with condensed chromatin and having no nucleoli is described. The mechanism and consequences of interference of PMA on anaphase are discussed.
Insights
Phorbol myristate acetate (PMA) disrupts mouse oocyte spindle function during meiosis I, blocking cell division. Puromycin (PU) can induce a reversible interphase, leading to pronuclei formation.
Area of Science:
- Cell Biology
- Developmental Biology
- Reproductive Biology
Background:
- Meiosis is crucial for gamete formation, involving precise chromosome segregation.
- Oocyte maturation is a complex process regulated by various signaling pathways.
- Understanding the molecular mechanisms of meiotic arrest and progression is essential.
Purpose of the Study:
- To investigate the effects of phorbol myristate acetate (PMA) on mouse oocyte maturation divisions.
- To explore the impact of puromycin (PU) on PMA-induced changes in oocyte maturation.
- To elucidate the role of protein phosphorylation in PMA-mediated spindle dysfunction.
Main Methods:
- Cytological observation of mouse oocytes undergoing maturation.
- Treatment with phorbol myristate acetate (PMA) and puromycin (PU).
- Analysis of spindle morphology, karyokinesis, and nuclear formation.
Main Results:
- PMA altered spindle morphology and function, leading to blocked karyokinesis in meiosis I.
- PMA-treated oocytes showed abnormal anaphase progression and chromosome segregation.
- PU induced a reversible interphase with pronuclei formation, including a novel class of nuclei with condensed chromatin.
Conclusions:
- PMA interferes with key events of meiotic spindle function and chromosome segregation.
- PU can override PMA-induced meiotic arrest, suggesting a role for protein synthesis in oocyte activation.
- The study reveals novel insights into the regulation of oocyte maturation and potential mechanisms of meiotic errors.
