Polo-like kinase 1 (PLK1) is involved in essential events of cell cycle including mitosis in which it participates in centrosomal microtubule nucleation, spindle bipolarity establishment and cytokinesis. Although PLK1 function has been studied in cycling cancer cells, only limited data are known about its role in the first mitosis of mammalian zygotes. During the 1-cell stage of mouse embryo development, the acentriolar spindle is formed and the shift from acentriolar to centrosomal spindle formation progresses gradually throughout the preimplantation stage, thus providing a unique possibility to study acentriolar spindle formation. We have shown previously that PLK1 activity is not essential for entry into first mitosis, but is required for correct spindle formation and anaphase onset in 1-cell mouse embryos. In the present study, we extend this knowledge by employing quantitative confocal live cell imaging to determine spindle formation kinetics in the absence of PLK1 activity and answer the question whether metaphase arrest at PLK1-inhibited embryos is associated with low anaphase-promoting complex/cyclosome (APC/C) activity and consequently high securin level. We have shown that inhibition of PLK1 activity induces a delay in onset of acentriolar spindle formation during first mitosis. Although these PLK1-inhibited 1-cell embryos were finally able to form a bipolar spindle, not all chromosomes were aligned at the metaphase equator. PLK1-inhibited embryos were arrested in metaphase without any sign of APC/C activation with high securin levels. Our results document that PLK1 controls the onset of spindle assembly and spindle formation, and is essential for APC/C activation before anaphase onset in mouse zygotes.
- MeSH
- anafáze MeSH
- anafázi podporující komplex metabolismus MeSH
- aparát dělícího vřeténka metabolismus MeSH
- blastocysta MeSH
- časosběrné zobrazování MeSH
- centrozom metabolismus MeSH
- kinetika MeSH
- kinetochory metabolismus MeSH
- konfokální mikroskopie MeSH
- mitóza MeSH
- myši MeSH
- protein-serin-threoninkinasy antagonisté a inhibitory metabolismus MeSH
- proteiny buněčného cyklu antagonisté a inhibitory metabolismus MeSH
- protoonkogenní proteiny antagonisté a inhibitory metabolismus MeSH
- pteridiny farmakologie MeSH
- zvířata MeSH
- zygota účinky léků metabolismus MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Aurora-A kinase (AURKA), a member of the serine/threonine protein kinase family, is involved in multiple steps of mitotic progression. It regulates centrosome maturation, mitotic spindle formation, and cytokinesis. While studied extensively in somatic cells, little information is known about AURKA in the early cleavage mouse embryo with respect to acentrosomal spindle assembly. In vitro experiments in which AURKA was inactivated with specific inhibitor MLN8237 during the early stages of embryogenesis documented gradual arrest in the cleavage ability of the mouse embryo. In the AURKA-inhibited 1-cell embryos, spindle formation and anaphase onset were delayed and chromosome segregation was defective. AURKA inhibition increased apoptosis during early embryonic development. In conclusion these data suggest that AURKA is essential for the correct chromosome segregation in the first mitosis as a prerequisite for normal later development after first cleavage.
- MeSH
- aurora kinasa A antagonisté a inhibitory metabolismus MeSH
- azepiny farmakologie MeSH
- časosběrné zobrazování MeSH
- fluorescenční mikroskopie MeSH
- fosforylace účinky léků MeSH
- inhibitory proteinkinas farmakologie MeSH
- konfokální mikroskopie MeSH
- kultivace embrya MeSH
- mitóza účinky léků fyziologie MeSH
- myši inbrední BALB C MeSH
- myši inbrední C57BL MeSH
- pyrimidiny farmakologie MeSH
- segregace chromozomů účinky léků fyziologie MeSH
- zvířata MeSH
- zygota účinky léků fyziologie MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
