scholarly journals Mitotic spindle assembly in vitro

Nature ◽  
1974 ◽  
Vol 250 (5463) ◽  
pp. 185-185
Author(s):  
Keyword(s):  
Mitotic Spindle ◽  
Spindle Assembly ◽  
Mitotic Spindle Assembly

scholarly journals Ensconsin/Map7 promotes microtubule growth and centrosome separation in Drosophila neural stem cells

2014 ◽  
Vol 204 (7) ◽  
pp. 1111-1121 ◽  
Author(s):  
Emmanuel Gallaud ◽  
Renaud Caous ◽  
Aude Pascal ◽  
Franck Bazile ◽  
Jean-Philippe Gagné ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Spindle Assembly ◽  
Microtubule Associated Proteins ◽  
Microtubule Polymerization ◽  
Sister Chromatids ◽  
Centrosome Separation ◽  
Associated Proteins ◽  
Microtubule Growth ◽  
Mitotic Spindle Assembly

The mitotic spindle is crucial to achieve segregation of sister chromatids. To identify new mitotic spindle assembly regulators, we isolated 855 microtubule-associated proteins (MAPs) from Drosophila melanogaster mitotic or interphasic embryos. Using RNAi, we screened 96 poorly characterized genes in the Drosophila central nervous system to establish their possible role during spindle assembly. We found that Ensconsin/MAP7 mutant neuroblasts display shorter metaphase spindles, a defect caused by a reduced microtubule polymerization rate and enhanced by centrosome ablation. In agreement with a direct effect in regulating spindle length, Ensconsin overexpression triggered an increase in spindle length in S2 cells, whereas purified Ensconsin stimulated microtubule polymerization in vitro. Interestingly, ensc-null mutant flies also display defective centrosome separation and positioning during interphase, a phenotype also detected in kinesin-1 mutants. Collectively, our results suggest that Ensconsin cooperates with its binding partner Kinesin-1 during interphase to trigger centrosome separation. In addition, Ensconsin promotes microtubule polymerization during mitosis to control spindle length independent of Kinesin-1.

scholarly journals Nup98 regulates bipolar spindle assembly through association with microtubules and opposition of MCAK

2011 ◽  
Vol 22 (5) ◽  
pp. 661-672 ◽  
Author(s):  
Marie K. Cross ◽  
Maureen A. Powers
Keyword(s):  
Nuclear Pore Complex ◽  
Mitotic Spindle ◽  
Spindle Assembly ◽  
Microtubule Dynamics ◽  
Nuclear Pore ◽  
Bipolar Spindle ◽  
Terminal Domain ◽  
C Terminus ◽  
Mitotic Spindle Assembly

During mitosis, the nuclear pore complex is disassembled and, increasingly, nucleoporins are proving to have mitotic functions when released from the pore. We find a contribution of the nucleoporin Nup98 to mitotic spindle assembly through regulation of microtubule dynamics. When added to Xenopus extract spindle assembly assays, the C-terminal domain of Nup98 stimulates uncontrolled growth of microtubules. Conversely, inhibition or depletion of Nup98 leads to formation of stable monopolar spindles. Spindle bipolarity is restored by addition of purified, recombinant Nup98 C-terminus. The minimal required region of Nup98 corresponds to a portion of the C-terminal domain lacking a previously characterized function. We show association between this region of the C-terminus of Nup98 and both Taxol-stabilized microtubules and the microtubule-depolymerizing mitotic centromere–associated kinesin (MCAK). Importantly, we demonstrate that this domain of Nup98 inhibits MCAK depolymerization activity in vitro. These data support a model in which Nup98 interacts with microtubules and antagonizes MCAK activity, thus promoting bipolar spindle assembly.

scholarly journals Human Ovarian Granulosa Cells Isolated during an IVF Procedure Exhibit Differential Expression of Genes Regulating Cell Division and Mitotic Spindle Formation

2019 ◽  
Vol 8 (12) ◽  
pp. 2026
Author(s):  
Maciej Brązert ◽  
Wiesława Kranc ◽  
Błażej Chermuła ◽  
Katarzyna Kowalska ◽  
Maurycy Jankowski ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Granulosa Cells ◽  
Mitotic Spindle ◽  
Spindle Assembly ◽  
In Vitro Cultivation ◽  
Cellular Ultrastructure ◽  
Mitotic Spindle Assembly

Granulosa cells (GCs) are a population of somatic cells whose role after ovulation is progesterone production. GCs were collected from patients undergoing controlled ovarian stimulation during an in vitro fertilization procedure, and they were maintained for 1, 7, 15, and 30 days of in vitro primary culture before collection for further gene expression analysis. A study of genes involved in the biological processes of interest was carried out using expression microarrays. To validate the obtained results, Reverse Transcription quantitative Polymerase Chain Reaction (RT-qPCR) was performed. The direction of changes in the expression of the selected genes was confirmed in most of the examples. Six ontological groups (“cell cycle arrest”, “cell cycle process”, “mitotic spindle organization”, “mitotic spindle assembly checkpoint”, “mitotic spindle assembly”, and “mitotic spindle checkpoint”) were analyzed in this study. The results of the microarrays obtained by us allowed us to identify two groups of genes whose expressions were the most upregulated (FAM64A, ANLN, TOP2A, CTGF, CEP55, BIRC5, PRC1, DLGAP5, GAS6, and NDRG1) and the most downregulated (EREG, PID1, INHA, RHOU, CXCL8, SEPT6, EPGN, RDX, WNT5A, and EZH2) during the culture. The cellular ultrastructure showed the presence of structures characteristic of mitotic cell division: a centrosome surrounded by a pericentric matrix, a microtubule system, and a mitotic spindle connected to chromosomes. The main goal of the study was to identify the genes involved in mitotic division and to identify the cellular ultrastructure of GCs in a long-term in vitro culture. All of the genes in these groups were subjected to downstream analysis, and their function and relation to the ovarian environment are discussed. The obtained results suggest that long-term in vitro cultivation of GCs may lead to their differentiation toward another cell type, including cells with cancer-like characteristics.

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