During mitosis and meiosis, the spindle assembly checkpoint acts to maintain genome stability by delaying cell division until accurate chromosome segregation can be guaranteed. Accuracy requires that chromosomes become correctly attached to the microtubule spindle apparatus via their kinetochores. When not correctly attached to the spindle, kinetochores activate the spindle assembly checkpoint network, which in turn blocks cell cycle progression. Once all kinetochores become stably attached to the spindle, the checkpoint is inactivated, which alleviates the cell cycle block and thus allows chromosome segregation and cell division to proceed. Here we review recent progress in our understanding of how the checkpoint signal is generated, how it blocks cell cycle progression and how it is extinguished.
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http://dx.doi.org/10.1016/j.cub.2012.10.006 | DOI Listing |
Dev Cell
December 2024
Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany; Cell Biology and Biophysics Unit, EMBL, 69117 Heidelberg, Germany. Electronic address:
Centrosomes organize microtubules that are essential for mitotic divisions in animal cells. They consist of centrioles surrounded by pericentriolar material (PCM). Questions related to mechanisms of centriole assembly, PCM organization, and spindle microtubule formation remain unanswered, partly due to limited availability of molecular-resolution structural data inside cells.
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2024
Guangzhou Key Laboratory of Metabolic Diseases and Reproductive Health, Guangdong-Hong Kong Metabolism & Reproduction Joint Laboratory, Reproductive Medicine Center, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Guangzhou, 510317, China.
Aneuploidy eggs are a common cause of human infertility, spontaneous abortion, or trisomy syndromes. The spindle assembly checkpoint (SAC) plays a crucial role in preventing aneuploidy in oocytes, yet it is unclear if additional mechanisms exist to ensure oocyte adherence to this checkpoint. It is now revealed that the microtubule-associated protein NUSAP can prevent oocytes from evading the SAC and regulate the speed of the cell cycle.
View Article and Find Full Text PDFPLoS Genet
December 2024
Department of Biology, McGill University, Montréal, Canada.
Stem and progenitor cell mitosis is essential for tissue development and homeostasis. How these cells ensure proper chromosome segregation, and thereby maintain mitotic fidelity, in the complex physiological environment of a living animal is poorly understood. Here we use in situ live-cell imaging of C.
View Article and Find Full Text PDFHistone tail phosphorylation has diverse effects on a myriad of cellular processes, including cell division, and is highly conserved throughout eukaryotes. Histone H3 phosphorylation at threonine 3 (H3T3) during mitosis occurs at the inner centromeres and is required for proper biorientation of chromosomes on the mitotic spindle. While H3T3 is also phosphorylated during meiosis, a possible role for this modification has not been tested.
View Article and Find Full Text PDFCurr Protoc
December 2024
Department of Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas.
These protocols describe a detailed method to determine the DNA damage and F-actin and microtubule defects of metaphase II oocytes caused by hexavalent chromium, Cr(VI), an endocrine disrupting chemical (EDC). The protocol provides systematic steps to determine protein expression encoded by pluripotency proteins such as Oct4, Nanog, and Cdx2 during early embryonic development. Occupational or environmental exposure to EDCs has significantly increased infertility in both men and women.
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