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Updated: Jun 25, 2025
Xenopus laevis as a Model to Identify Translation Impairment
Published on: September 27, 2015
Multiple intersecting pathways are involved in CPEB1 phosphorylation and regulation of translation during mouse
Chisato Kunitomi1,2,3, Mayra Romero4,5, Enrico Maria Daldello6
1Center for Reproductive Sciences, University of California, San Francisco, CA 94143, USA.
Abstract:
The RNA-binding protein cytoplasmic polyadenylation element binding 1 (CPEB1) plays a fundamental role in regulating mRNA translation in oocytes. However, the specifics of how and which protein kinase cascades modulate CPEB1 activity are still controversial. Using genetic and pharmacological tools, and detailed time courses, we have re-evaluated the relationship between CPEB1 phosphorylation and translation activation during mouse oocyte maturation. We show that both the CDK1/MAPK and AURKA/PLK1 pathways converge on CPEB1 phosphorylation during prometaphase of meiosis I. Only inactivation of the CDK1/MAPK pathway disrupts translation, whereas inactivation of either pathway alone leads to CPEB1 stabilization. However, CPEB1 stabilization induced by inactivation of the AURKA/PLK1 pathway does not affect translation, indicating that destabilization and/or degradation is not linked to translational activation. The accumulation of endogenous CCNB1 protein closely recapitulates the translation data that use an exogenous template. These findings support the overarching hypothesis that the activation of translation during prometaphase in mouse oocytes relies on a CDK1/MAPK-dependent CPEB1 phosphorylation, and that translational activation precedes CPEB1 destabilization.
Insights
Mouse oocyte maturation relies on cytoplasmic polyadenylation element binding 1 (CPEB1) phosphorylation. The CDK1/MAPK pathway, not AURKA/PLK1, is crucial for translation activation during prometaphase.
Area of Science:
- Molecular and Cellular Biology
- Developmental Biology
- Reproductive Biology
Background:
- The RNA-binding protein cytoplasmic polyadenylation element binding 1 (CPEB1) is vital for mRNA translation regulation in oocytes.
- The precise protein kinase cascades modulating CPEB1 activity during oocyte maturation remain controversial.
Purpose of the Study:
- To re-evaluate the relationship between CPEB1 phosphorylation and translation activation during mouse oocyte maturation.
- To elucidate the roles of CDK1/MAPK and AURKA/PLK1 pathways in CPEB1 regulation.
Main Methods:
- Utilized genetic and pharmacological tools for pathway manipulation.
- Conducted detailed time-course analyses of CPEB1 phosphorylation and protein levels.
- Assessed translation activation using exogenous templates and endogenous CCNB1 accumulation.
Main Results:
- Both CDK1/MAPK and AURKA/PLK1 pathways converge on CPEB1 phosphorylation during meiosis I prometaphase.
- Only CDK1/MAPK pathway inactivation disrupts translation; inactivation of either pathway stabilizes CPEB1.
- CPEB1 stabilization by AURKA/PLK1 inactivation does not impact translation, decoupling stabilization from activation.
Conclusions:
- Translation activation during mouse oocyte prometaphase depends on CDK1/MAPK-mediated CPEB1 phosphorylation.
- Translational activation precedes CPEB1 destabilization, challenging previous assumptions.
- The findings clarify the distinct roles of signaling pathways in CPEB1 regulation and translation control.
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