Key steps in the execution of chromosome alignment and Biology Diagrams Defects in chromosome alignment are normally avoided by increased Aurora B activity at centromeres of misaligned chromosomes. 27 However, the correction of erroneous attachments underlying some chromosome alignment defects (e.g., syntelic attachments) appears to be less robust in cancer cells that also show overly stabilized kinetochore The kinetochore, the protein complex assembled at the centromere of each mitotic chromosome, serves as the attachment site for the spindle MTs. A combination of forces generated by kinetochores and microtubule dynamics is thought to contribute to kinetochore-MT attachment and chromosome movement in achieving metaphase chromosome alignment. (We defined misaligned chromosomes in metaphase as chromosomes that failed to align with the majority of chromosomes at metaphase plates.) (SD) from at least three independent experiments. For chromosome segregation defects, 100 mitotic cells were analyzed for each RNAi experiment. Scale bars in (C) and (D), 20 μm.
Chromosome misalignments cause spindle misorientation. To study the role of Spindly in spindle positioning, we filmed cells grown on rectangular‐shaped micropatterns and measured the angle of the metaphase plate relative to the short cell axis (Fig (Fig1A). 1 A). Since Spindly depletion leads to chromosome alignment defects associated with a profound delay in mitosis (20 and Fig EV1 A), we Intriguingly, FISH with chromosome-specific probes showed that, despite the defects resulting from KIF18A inactivation, there were no detectable alterations in chromosome copy number . Overall, these data suggest that although chromosome alignment prevents the formation of lagging chromosomes and micronuclei in anaphase, mechanisms exist that Similar metaphase chromosome alignment defects were observed in cycled egg extracts (Figures S1A and S1C), in which sperm chromatin had undergone DNA replication and were arrested at the subsequent M phase. To strengthen these results in cycled egg extracts, we sought to inhibit the MRN activity through independent means by addition of a
Micronuclei from misaligned chromosomes that satisfy the spindle ... Biology Diagrams
PAK2 is essential for chromosome alignment in metaphase I oocytes. The specific localization of PAK2 during oocyte maturation prompted us to ask whether Pak2 functions in the chromosome alignment Downregulation of ERK2 leads to chromosome alignment defects.A, siRNA knockdown of ERK2. B, Compared with the overexpression of ERK2, overexpression of ERK2-2A led to a significant increase in cells with chromosome alignment defects in metaphase (ERK2 = 28.7 ± 4.4, p = 0.1438; ERK2-2A = 49.7 ± 3.0, p < 0.01;
