scholarly journals The Zebra fish cassiopeia Mutant Reveals that SIL Is Required for Mitotic Spindle Organization

2007 ◽  
Vol 27 (16) ◽  
pp. 5887-5897 ◽  
Author(s):  
Kathleen L. Pfaff ◽  
Christian T. Straub ◽  
Ken Chiang ◽  
Daniel M. Bear ◽  
Yi Zhou ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Human Cells ◽  
Zebra Fish ◽  
Loss Of Function ◽  
Mitotic Spindles ◽  
Hairpin Rna ◽  
Chromosome Separation ◽  
Mitotic Spindle Assembly ◽  
Short Hairpin ◽  
Rna Knockdown

ABSTRACT A critical step in cell division is formation of the mitotic spindle, which is a bipolar array of microtubules that mediates chromosome separation. Here, we report that the SCL-interrupting locus (SIL), a vertebrate-specific cytosolic protein, is necessary for proper mitotic spindle organization in zebrafish and human cells. A homozygous lethal zebrafish mutant, cassiopeia (csp), was identified by a genetic screen for mitotic mutant. csp mutant embryos have an increased mitotic index, have highly disorganized mitotic spindles, and often lack one or both centrosomes. These phenotypes are caused by a loss-of-function mutation in zebrafish sil. To determine if the requirement for SIL in mitotic spindle organization is conserved in mammals, we generated an antibody against human SIL, which revealed that SIL localizes to the poles of the mitotic spindle during metaphase. Furthermore, short hairpin RNA knockdown of SIL in human cells recapitulates the zebrafish csp mitotic spindle defects. These data, taken together, identify SIL as a novel, vertebrate-specific regulator of mitotic spindle assembly.

scholarly journals Short Hairpin RNA Knockdown of the Androgen Receptor Attenuates Ligand-Independent Activation and Delays Tumor Progression

2006 ◽  
Vol 66 (21) ◽  
pp. 10613-10620 ◽  
Author(s):  
Helen Cheng ◽  
Rob Snoek ◽  
Fariba Ghaidi ◽  
Michael E. Cox ◽  
Paul S. Rennie
Keyword(s):  
Androgen Receptor ◽  
Tumor Progression ◽  
Short Hairpin Rna ◽  
Hairpin Rna ◽  
Short Hairpin ◽  
Rna Knockdown

scholarly journals Adducin-1 is essential for mitotic spindle assembly through its interaction with myosin-X

2013 ◽  
Vol 204 (1) ◽  
pp. 19-28 ◽  
Author(s):  
Po-Chao Chan ◽  
Rosaline Y.C. Hsu ◽  
Chih-Wei Liu ◽  
Chien-Chen Lai ◽  
Hong-Chen Chen
Keyword(s):  
Mitotic Spindle ◽  
Spindle Assembly ◽  
Actin Binding ◽  
Cyclin Dependent Kinase ◽  
Mitotic Spindles ◽  
Mitotic Progression ◽  
Filamentous Actin ◽  
Multipolar Spindles ◽  
Mitotic Spindle Assembly ◽  
Myosin X

Mitotic spindles are microtubule-based structures, but increasing evidence indicates that filamentous actin (F-actin) and F-actin–based motors are components of these structures. ADD1 (adducin-1) is an actin-binding protein that has been shown to play important roles in the stabilization of the membrane cortical cytoskeleton and cell–cell adhesions. In this study, we show that ADD1 associates with mitotic spindles and is crucial for proper spindle assembly and mitotic progression. Phosphorylation of ADD1 at Ser12 and Ser355 by cyclin-dependent kinase 1 enables ADD1 to bind to myosin-X (Myo10) and therefore to associate with mitotic spindles. ADD1 depletion resulted in distorted, elongated, and multipolar spindles, accompanied by aberrant chromosomal alignment. Remarkably, the mitotic defects caused by ADD1 depletion were rescued by reexpression of ADD1 but not of an ADD1 mutant defective in Myo10 binding. Together, our findings unveil a novel function for ADD1 in mitotic spindle assembly through its interaction with Myo10.

Efficient Lentiviral Vectors for Short Hairpin RNA Delivery into Human Cells

2003 ◽  
Vol 14 (12) ◽  
pp. 1207-1212 ◽  
Author(s):  
Dong Sung An ◽  
Yiming Xie ◽  
Si Hua Mao ◽  
Kouki Morizono ◽  
Sam K.P. Kung ◽  
...  
Keyword(s):  
Lentiviral Vectors ◽  
Short Hairpin Rna ◽  
Human Cells ◽  
Hairpin Rna ◽  
Short Hairpin

scholarly journals Efficient immortalization of primary human cells by p16INK4a-specific short hairpin RNA or Bmi-1, combined with introduction of hTERT

2007 ◽  
Vol 98 (2) ◽  
pp. 147-154 ◽  
Author(s):  
Kei Haga ◽  
Shin-ichi Ohno ◽  
Takashi Yugawa ◽  
Mako Narisawa-Saito ◽  
Masatoshi Fujita ◽  
...  
Keyword(s):  
Short Hairpin Rna ◽  
Human Cells ◽  
Hairpin Rna ◽  
Short Hairpin ◽  
Primary Human Cells

scholarly journals Centrosome age regulates kinetochore–microtubule stability and biases chromosome mis-segregation

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Ivana Gasic ◽  
Purnima Nerurkar ◽  
Patrick Meraldi
Keyword(s):  
Stem Cell ◽  
Chromosome Segregation ◽  
Mitotic Spindle ◽  
Human Cells ◽  
Functional Asymmetry ◽  
Mitotic Spindles ◽  
Daughter Cells ◽  
Cell Divisions ◽  
Microtubule Stability ◽  
Stem Cell Divisions

The poles of the mitotic spindle contain one old and one young centrosome. In asymmetric stem cell divisions, the age of centrosomes affects their behaviour and their probability to remain in the stem cell. In contrast, in symmetric divisions, old and young centrosomes are thought to behave equally. This hypothesis is, however, untested. In this study, we show in symmetrically dividing human cells that kinetochore–microtubules associated to old centrosomes are more stable than those associated to young centrosomes, and that this difference favours the accumulation of premature end-on attachments that delay the alignment of polar chromosomes at old centrosomes. This differential microtubule stability depends on cenexin, a protein enriched on old centrosomes. It persists throughout mitosis, biasing chromosome segregation in anaphase by causing daughter cells with old centrosomes to retain non-disjoint chromosomes 85% of the time. We conclude that centrosome age imposes via cenexin a functional asymmetry on all mitotic spindles.

scholarly journals Microtubule poleward flux in human cells is driven by the coordinated action of four kinesins

2020 ◽  
Author(s):  
Yulia Steblyanko ◽  
Girish Rajendraprasad ◽  
Mariana Osswald ◽  
Susana Eibes ◽  
Stephan Geley ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Driving Force ◽  
Molecular Mechanisms ◽  
Human Cells ◽  
Flux Rate ◽  
Loss Of Function ◽  
Coordinated Action ◽  
Spindle Microtubules ◽  
And Function ◽  
Poleward Flux

AbstractMitotic spindle microtubules (MTs) undergo continuous poleward flux, whose driving force and function in humans remain unclear. Here, we combined loss-of-function screenings with analysis of MT dynamics in human cells to investigate the molecular mechanisms underlying MT-flux. We report that kinesin-7/CENP-E at kinetochores (KTs) is the predominant driver of MT-flux in early prometaphase, while kinesin-4/KIF4A on chromosome arms facilitates MT-flux during late prometaphase and metaphase. We show that both of these activities work in coordination with MT-crosslinking motors kinesin-5/EG5 and kinesin-12/KIF15. Our data further indicate that MT-flux driving force is transmitted from non-KT MTs to KT-MTs via MT-coupling by HSET and NuMA. Moreover, we found that MT-flux rate correlates with spindle size and this correlation depends on the establishment of stable end-on KT-MT attachments. Strikingly, we revealed that flux is required to counteract the kinesin 13/MCAK-dependent MT-depolymerization to regulate spindle length. Thus, our study demonstrates that MT-flux in human cells is driven by the coordinated action of four kinesins, and is required to regulate mitotic spindle size in response to MCAK-mediated MT-depolymerizing activity at KTs.

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