Regulation of stage-specific gene expression during early mouse development: effect of cytochalasin B and aphidicolin on stage-specific protein synthesis in mouse eggs
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Abstract:
Mechanisms regulating stage-specific translation in mouse embryos were studied by inhibitor experiments. When fertilized eggs were continuously treated with cytochalasin B, cleavage was prevented, whereas karyokinesis proceeded, resulting in protein synthesis patterns changing stage-specifically as in control embryos through preimplantation development. When fertilized eggs were continuously exposed to aphidicolin, cleavage and DNA synthesis were inhibited, thus keeping their protein synthesis at the level of fertilized eggs with few new polypeptides appearing after one day. The next day these eggs stopped translation almost completely. Stage-specific translation therefore might be controlled by nuclear replications rather than by cytoplasmic clock.
Insights
Stage-specific translation in mouse embryos is regulated by nuclear replication, not a cytoplasmic clock. Inhibitor experiments show DNA synthesis is key to protein synthesis patterns during early development.
Area of Science:
- Developmental Biology
- Molecular Embryology
- Cellular Regulation
Background:
- Understanding the molecular mechanisms governing early embryonic development is crucial.
- Stage-specific protein synthesis plays a vital role in preimplantation development.
- The precise regulators of translational control during these early stages remain incompletely understood.
Purpose of the Study:
- To investigate the regulatory mechanisms controlling stage-specific translation in mouse embryos.
- To determine whether nuclear replication or cytoplasmic factors drive changes in protein synthesis during early development.
Main Methods:
- Utilized inhibitor experiments on fertilized mouse eggs.
- Applied cytochalasin B to inhibit cleavage while allowing karyokinesis.
- Used aphidicolin to inhibit both cleavage and DNA synthesis.
Main Results:
- Cytochalasin B treatment allowed stage-specific protein synthesis patterns to emerge despite blocked cleavage.
- Aphidicolin treatment inhibited DNA synthesis, leading to arrested protein synthesis at the level of fertilized eggs.
- Prolonged aphidicolin exposure resulted in a near-complete cessation of translation.
Conclusions:
- Nuclear replication, rather than a cytoplasmic clock, appears to be the primary controller of stage-specific translation in early mouse embryos.
- DNA synthesis is essential for the progression of stage-specific protein synthesis during preimplantation development.