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Chromatin Immunoprecipitation Assay for Tissue-specific Genes using Early-stage Mouse Embryos
Published on: April 29, 2011
Mouse emi1 has an essential function in mitotic progression during early embryogenesis
Ho Lee1, Dong Jun Lee, Sang Phil Oh
1Department of Biological Sciences, Biomedical Research Center, Korea Advanced Institute of Science and Technology, 373-1 Guseoung-dong, Yuseong-gu, Daejeon 305-701, South Korea.
Abstract:
For successful mitotic entry and spindle assembly, mitosis-promoting factors are activated at the G(2)/M transition stage, followed by stimulation of the anaphase-promoting complex (APC), an E3 ubiquitin ligase, to direct the ordered destruction of several critical mitotic regulators. Given that inhibition of APC activity is important for preventing premature or improper ubiquitination and destruction of substrates, several modulators and their regulation mechanisms have been studied. Emi1, an early mitotic inhibitor, is one of these regulatory factors. Here we show, by analyzing Emi1-deficient embryos, that Emi1 is essential for precise mitotic progression during early embryogenesis. Emi1(-/-) embryos were found to be lethal due to a defect in preimplantation development. Cell proliferation appeared to be normal, but mitotic progression was severely defective during embryonic cleavage. Moreover, multipolar spindles and misaligned chromosomes were frequently observed in Emi1 mutant cells, possibly due to premature APC activation. Our results collectively suggest that the late prophase checkpoint function of Emi1 is essential for accurate mitotic progression and embryonic viability.
Insights
Early mitotic inhibitor Emi1 is crucial for embryonic development. Emi1 deficiency in embryos leads to lethal mitotic defects, highlighting its essential role in precise cell division and embryonic viability.
Area of Science:
- Cell Biology
- Developmental Biology
- Genetics
Background:
- Successful mitosis requires precise regulation of cell cycle transitions, including the G(2)/M phase.
- The anaphase-promoting complex (APC) is a key E3 ubiquitin ligase controlling mitotic progression by degrading regulatory proteins.
- Inhibition of APC activity is vital to prevent premature substrate degradation, necessitating regulatory factors like early mitotic inhibitor 1 (Emi1).
Purpose of the Study:
- To investigate the essential role of Emi1 in mitotic progression during early embryogenesis.
- To determine the consequences of Emi1 deficiency on embryonic development and cell division.
Main Methods:
- Analysis of Emi1-deficient (Emi1(-/-)) mouse embryos.
- Assessment of cell proliferation and mitotic progression during embryonic cleavage.
- Microscopic examination of spindle formation and chromosome alignment in Emi1 mutant cells.
Main Results:
- Emi1(-/-) embryos exhibited lethality due to defects in preimplantation development.
- While cell proliferation appeared normal, mitotic progression was severely impaired during embryonic cleavage.
- Emi1 mutant cells frequently displayed multipolar spindles and misaligned chromosomes, indicative of premature APC activation.
Conclusions:
- Emi1 is essential for accurate mitotic progression in early embryogenesis.
- The late prophase checkpoint function of Emi1 is critical for maintaining genomic stability and embryonic viability.
- Loss of Emi1 disrupts the precise regulation of the cell cycle, leading to developmental failure.
