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Wee1 is a cell cycle regulator that phosphorylates Cdk1/Cdc2 and inhibits G2/M transition. Loss of Wee1 in fission yeast results in an early onset of mitosis. Interestingly, we found that cells lacking Wee1 require the functional spindle checkpoint for their viability. Genetic analysis indicated that the requirement is not attributable to the early onset of mitosis. Live-cell imaging revealed that some kinetochores are not attached or bioriented in the mutant. Furthermore, Mad2, a component of the spindle checkpoint known to recognize unattached kinetochores, accumulates in the vicinity of the spindle, representing activation of the spindle checkpoint in the mutant. It appears that the mutant cannot maintain stable kinetochore-microtubule attachment, and relies on the delay imposed by the spindle checkpoint for establishing biorientation of kinetochores. This study revealed a role of Wee1 in ensuring accurate segregation of chromosomes during mitosis, and thus provided a basis for a new principle of cancer treatment with Wee1 inhibitors.
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http://dx.doi.org/10.1098/rsob.230379 | DOI Listing |
Zygote
September 2025
Field Centre for Sustainable Agriculture, Faculty of Agriculture, Niigata University, Niigata, Japan.
Aneuploidy in oocytes is a leading cause of implantation failure, miscarriage and congenital disorders. During meiosis, proper timing of chromosome segregation is regulated by the spindle assembly checkpoint (SAC) and the anaphase-promoting complex/cyclosome (APC/C). However, how pharmacological manipulation of these regulatory pathways affects aneuploidy remains incompletely understood.
View Article and Find Full Text PDFBiomolecules
August 2025
Department of Genetics, Cell Biology & Development, University of Minnesota, Minneapolis, MN 55455, USA.
Histone 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 PDFAm J Obstet Gynecol
August 2025
State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, China; Center of Reproduction and Genetics, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Suzhou, China; Innova
Background: During mammalian oocyte meiosis, accurate chromosome segregation critically depends on precise regulation of kinetochore-microtubule (K-MT) attachments, a process monitored by the spindle assembly checkpoint (SAC). While CENP-F has been well characterized as a kinetochore-associated protein that stabilizes K-MT connections during mitosis, its functional mechanisms during meiosis remain poorly understood. In particular, there is still controversy over whether farnesylation modification governs localization and functionality of CENP-F.
View Article and Find Full Text PDFBioessays
August 2025
Zentrum Für Molekulare Biologie Der Universität Heidelberg (ZMBH), Deutsches Krebsforschungszentrum (DKFZ)-ZMBH Allianz, Universität Heidelberg, Heidelberg, Germany.
Mitosis is a crucial phase of the cell cycle, during which several mechanisms work together to ensure accurate chromosome segregation and to eliminate defective cells if errors occur. One key mechanism is the spindle assembly checkpoint (SAC), which upon mitotic errors-such as those induced by genetic mutations, drug treatments, or environmental stresses-arrest cells in mitosis. Arrested cells may undergo apoptosis during mitosis or eventually exit mitosis even if the damage remains unrepaired.
View Article and Find Full Text PDFExploration (Beijing)
August 2025
Research Unit of Radiation Oncology Chinese Academy of Medical Sciences Jinan Shandong China.
Radiotherapy (RT) resistance remains a substantial challenge in cancer therapy. Although physical factors are optimizing, the biological mechanisms for RT resistance are still elusive. Herein, we explored potential reasons for this difficult problem by generating RT-resistant models for in vitro and in vivo experiments.
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