The spindle assembly checkpoint monitors the integrity of the spindle microtubules, which attach to sister chromatids at kinetochores and play a vital role in preserving genome stability by preventing missegregation. A key target of the spindle assembly checkpoint is securin, the separase inhibitor. In budding yeast, loss of securin results in precocious sister chromatid separation when the microtubule spindle is disrupted. However, in contrast to budding yeast, mammalian securin is not required for spindle checkpoint, suggesting that there are redundant mechanisms controlling the dissolution of sister chromatid cohesion in the absence of securin. One candidate mechanism is the inhibitory phosphorylation of separase. We generated a nonphosphorylable point mutant (S1121A) separase allele in securin-/- mouse embryonic stem cells. Securin(-/-)separase(+/S1121A) cells are viable but fail to maintain sister chromatid cohesion in response to the disruption of spindle microtubules, show enhanced sensitivity to nocodazole, and cannot recover from prometaphase arrest.
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http://dx.doi.org/10.1091/mbc.e05-03-0190 | DOI Listing |
PLoS One
January 2025
Department of Life Science and Medical Bioscience, Laboratory of Cytoskeletal Logistics, Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku, Tokyo, Japan.
In mammalian epithelial cells, cytoplasmic microtubules are mainly non-centrosomal, through the functions of the minus-end binding proteins CAMSAP2 and CAMSAP3. When cells enter mitosis, cytoplasmic microtubules are reorganized into the spindle composed of both centrosomal and non-centrosomal microtubules. The function of the CAMSAP proteins upon spindle assembly remains unknown, as these do not exhibit evident localization to spindle microtubules.
View Article and Find Full Text PDFMedicina (Kaunas)
November 2024
Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif 21944, Saudi Arabia.
: Invasive breast cancer (BC) was traditionally investigated visually, and no technique could identify the key molecular drivers of patient survival. However, essential molecular drivers of invasive BC have now been discovered using innovative genomic, transcriptomic, and proteomic methodologies. Nevertheless, few evaluations of the prognostic factors of BC in Saudi Arabia have been performed.
View Article and Find Full Text PDFTurk J Gastroenterol
December 2024
Department of Emergency Medicine, Shandong University, Qilu Hospital (Qingdao), Cheeloo College of Medicine, Qingdao, China.
Metabolic dysfunction-associated steatotic liver disease (MASLD) is considered the most widespread chronic liver condition globally. Genome-wide association studies (GWAS) have pinpointed several genetic loci correlated to MASLD, yet the biological significance of these loci remains poorly understood. Initially, we applied Functional Mapping and Annotation (FUMA) to conduct a functional annotation of the MASLD GWAS summary statistics, which included data from 3242 cases and 707 631 controls.
View Article and Find Full Text PDFPreserving a large number of essential yet highly unstable ribosomal DNA (rDNA) repeats is critical for the germline to perpetuate the genome through generations. Spontaneous rDNA loss must be countered by rDNA copy number (CN) expansion. Germline rDNA CN expansion is best understood in Drosophila melanogaster, which relies on unequal sister chromatid exchange (USCE) initiated by DNA breaks at rDNA.
View Article and Find Full Text PDFNat Commun
December 2024
Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
Aneuploidy in eggs is a leading cause of miscarriages or viable developmental syndromes. Aneuploidy rates differ between individual chromosomes. For instance, chromosome 21 frequently missegregates, resulting in Down Syndrome.
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