Quinacrine-induced changes in mitotic PtK1 spindle microtubule organization

1987 ◽  
Vol 7 (1) ◽  
pp. 10-19 ◽  
Author(s):  
Lydia Armstrong ◽  
Judith Armstrong Snyder
Keyword(s):  
Microtubule Organization ◽  
Spindle Microtubule ◽  
Induced Changes

AtNUF2 modulates spindle microtubule organization and chromosome segregation during mitosis

2021 ◽  
Author(s):  
Jin Li ◽  
Yutao Wang ◽  
Wenxuan Zou ◽  
Liufang Jian ◽  
Ying Fu ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
Microtubule Organization ◽  
Spindle Microtubule

Ultrastructural Features of Spindle Microtubule Organization During the Neclear Division of Encephalitozoon hellem

1997 ◽  
Vol 44 (s6) ◽  
pp. 80s-80s ◽  
Author(s):  
LUCIANO SACCHI ◽  
ELISA BIGLIARDI ◽  
PAOLO LANZARINI ◽  
SILVIA CORONA ◽  
SIMONETTA GATTI ◽  
...  
Keyword(s):  
Microtubule Organization ◽  
Spindle Microtubule

scholarly journals Tektin 2 is required for central spindle microtubule organization and the completion of cytokinesis

2008 ◽  
Vol 181 (4) ◽  
pp. 595-603 ◽  
Author(s):  
Thomas M. Durcan ◽  
Elizabeth S. Halpin ◽  
Trisha Rao ◽  
Nicholas S. Collins ◽  
Emily K. Tribble ◽  
...  
Keyword(s):  
Cell Formation ◽  
Binucleate Cell ◽  
Aurora B ◽  
Microtubule Organization ◽  
Spindle Microtubule ◽  
Central Spindle ◽  
Daughter Cells ◽  
Spindle Poles ◽  
Spindle Midzone ◽  
Interfering Rna

During anaphase, the nonkinetochore microtubules in the spindle midzone become compacted into the central spindle, a structure which is required to both initiate and complete cytokinesis. We show that Tektin 2 (Tek2) associates with the spindle poles throughout mitosis, organizes the spindle midzone microtubules during anaphase, and assembles into the midbody matrix surrounding the compacted midzone microtubules during cytokinesis. Tek2 small interfering RNA (siRNA) disrupts central spindle organization and proper localization of MKLP1, PRC1, and Aurora B to the midzone and prevents the formation of a midbody matrix. Video microscopy revealed that loss of Tek2 results in binucleate cell formation by aberrant fusion of daughter cells after cytokinesis. Although a myosin II inhibitor, blebbistatin, prevents actin-myosin contractility, the microtubules of the central spindle are compacted. Strikingly, Tek2 siRNA abolishes this actin-myosin–independent midzone microtubule compaction. Thus, Tek2-dependent organization of the central spindle during anaphase is essential for proper midbody formation and the segregation of daughter cells after cytokinesis.

scholarly journals MCAK and Paclitaxel Have Differential Effects on Spindle Microtubule Organization and Dynamics

2009 ◽  
Vol 20 (6) ◽  
pp. 1639-1651 ◽  
Author(s):  
Rania S. Rizk ◽  
Kevin P. Bohannon ◽  
Laura A. Wetzel ◽  
James Powers ◽  
Sidney L. Shaw ◽  
...  
Keyword(s):  
Fluorescence Intensity ◽  
Mitotic Spindle ◽  
Fluorescence Recovery After Photobleaching ◽  
Microtubule Dynamics ◽  
Microtubule Organization ◽  
Spindle Microtubule ◽  
Quantitative Immunofluorescence ◽  
Spindle Microtubules ◽  
Low Levels ◽  
Paclitaxel Treatment

Within the mitotic spindle, there are multiple populations of microtubules with different turnover dynamics, but how these different dynamics are maintained is not fully understood. MCAK is a member of the kinesin-13 family of microtubule-destabilizing enzymes that is required for proper establishment and maintenance of the spindle. Using quantitative immunofluorescence and fluorescence recovery after photobleaching, we compared the differences in spindle organization caused by global suppression of microtubule dynamics, by treating cells with low levels of paclitaxel, versus specific perturbation of spindle microtubule subsets by MCAK inhibition. Paclitaxel treatment caused a disruption in spindle microtubule organization marked by a significant increase in microtubules near the poles and a reduction in K-fiber fluorescence intensity. This was correlated with a faster t1/2 of both spindle and K-fiber microtubules. In contrast, MCAK inhibition caused a dramatic reorganization of spindle microtubules with a significant increase in astral microtubules and reduction in K-fiber fluorescence intensity, which correlated with a slower t1/2 of K-fibers but no change in the t1/2 of spindle microtubules. Our data support the model that MCAK perturbs spindle organization by acting preferentially on a subset of microtubules, and they support the overall hypothesis that microtubule dynamics is differentially regulated in the spindle.

scholarly journals Dynamics of spindle microtubule organization: kinetochore fiber microtubules of plant endosperm.

1982 ◽  
Vol 92 (2) ◽  
pp. 540-558 ◽  
Author(s):  
C G Jensen
Keyword(s):  
Careful Analysis ◽  
Cross Sectional Area ◽  
Time Dependent ◽  
Sectional Area ◽  
Organizational Changes ◽  
Microtubule Organization ◽  
Spindle Microtubule ◽  
Cross Sectional ◽  
Kinetochore Region ◽  
Serial Section Reconstruction

Organization of kinetochore fiber microtubules (MTs) throughout mitosis in the endosperm of Haemanthus katherinae Bak. has been analysed using serial section reconstruction from electron micrographs. Accurate and complete studies have required careful analysis of individual MTs in precisely oriented serial sections through many (45) preselected cells. Kinetochore MTs (kMTs) and non-kinetochore MTs (nkMTs) intermingle within the fiber throughout division, undergoing characteristic, time-dependent, organizational changes. The number of kMTs increases progressively throughout the kinetochore during prometaphase-metaphase. Prometaphase chromosomes which were probably moving toward the pole at the time of fixation have unequally developed kinetochores associated with many nkMTs. The greatest numbers of kMTs (74-109/kinetochore), kinetochore cross-sectional area, and kMT central density all occur at metaphase. Throughout anaphase and telophase there is a decrease in the number of kMTs and, in the kinetochore cross-sectional area, an increased obliquity of kMTs and increased numbers of short MTs near the kinetochore. Delayed kinetochores possess more kMTs than do kinetochores near the poles, but fewer kMTs than chromosomes which have moved equivalent distances in other cells. The frequency of C-shaped proximal MT terminations within kinetochores is highest at early prometaphase and midtelophase, falling to zero at midanaphase. Therefore, in Haemanthus, MTs are probably lost from the periphery of the kinetochore during anaphase in a manner which is related to both time and position of the chromosome along the spindle axis. The complex, time-dependent organization of MTs in the kinetochore region strongly suggests that chromosome movement is accompanied by continual MT rearrangement and/or assembly/disassembly.

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