scholarly journals Plasmodium berghei Kinesin-5 Associates With the Spindle Apparatus During Cell Division and Is Important for Efficient Production of Infectious Sporozoites

2020 ◽  
Vol 10 ◽  
Author(s):  
Mohammad Zeeshan ◽  
Declan Brady ◽  
Rebecca R. Stanway ◽  
Carolyn A. Moores ◽  
Anthony A. Holder ◽  
...  
Keyword(s):  
Cell Division ◽  
Plasmodium Berghei ◽  
Efficient Production ◽  
Spindle Apparatus

scholarly journals Plasmodium berghei kinesin-5 associates with the spindle apparatus during cell division and is important for efficient production of infectious sporozoites

2020 ◽  
Author(s):  
Mohammad Zeeshan ◽  
Declan Brady ◽  
Rebecca R. Stanway ◽  
Carolyn A. Moores ◽  
Anthony A. Holder ◽  
...  
Keyword(s):  
Cell Division ◽  
Plasmodium Berghei ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Subcellular Location ◽  
Live Cell ◽  
Efficient Production ◽  
Spindle Apparatus ◽  
Partial Overlap ◽  
Fixed Cell

AbstractKinesin-5 motors play essential roles in spindle apparatus assembly during cell division, by generating forces to establish and maintain the spindle bipolarity essential for proper chromosome segregation. Kinesin-5 is largely conserved structurally and functionally in model eukaryotes, but its role is unknown in the Plasmodium parasite, an evolutionarily divergent organism with several atypical features of both mitotic and meiotic cell division. We have investigated the function and subcellular location of kinesin-5 during cell division throughout the Plasmodium berghei life cycle. Deletion of kinesin-5 had little visible effect at any proliferative stage except sporozoite production in oocysts, resulting in a significant decrease in the number of motile sporozoites in mosquito salivary glands, which were able to infect a new vertebrate host. Live-cell imaging showed kinesin-5-GFP located on the spindle and at spindle poles during both atypical mitosis and meiosis. Fixed-cell immunofluorescence assays revealed kinesin-5 co-localized with α-tubulin and centrin-2 and a partial overlap with kinetochore marker NDC80 during early blood stage schizogony. Dual-colour live-cell imaging showed that kinesin-5 is closely associated with NDC80 during male gametogony, but not with kinesin-8B, a marker of the basal body and axonemes of the forming flagella. Treatment of gametocytes with microtubule-specific inhibitors confirmed kinesin-5 association with nuclear spindles and not cytoplasmic axonemal microtubules. Altogether, our results demonstrate that kinesin-5 is associated with the spindle apparatus, expressed in proliferating parasite stages, and important for efficient production of infectious sporozoites.

scholarly journals Ubiquitin in regulation of spindle apparatus and its positioning: implications in development and disease

2015 ◽  
Vol 93 (4) ◽  
pp. 273-281 ◽  
Author(s):  
Devika Srivastava ◽  
Oishee Chakrabarti
Keyword(s):  
Cell Division ◽  
Developmental Disorders ◽  
Ubiquitin Ligases ◽  
Pivotal Role ◽  
Direct Connection ◽  
Post Translational Modification ◽  
E3 Ligases ◽  
Cellular Events ◽  
Spindle Apparatus

Emerging data implicates ubiquitination, a post-translational modification, in regulating essential cellular events, one of them being mitosis. In this review we discuss how various E3 ligases modulate the cortical proteins such as dynein, LGN, NuMa, Gα, along with polymerization, stability, and integrity of spindles. These are responsible for regulating symmetric cell division. Some of the ubiquitin ligases regulating these proteins include PARK2, BRCA1/BARD1, MGRN1, SMURF2, and SIAH1; these play a pivotal role in the correct positioning of the spindle apparatus. A direct connection between developmental or various pathological disorders and the ubiquitination mediated cortical regulation is rather speculative, though deletions or mutations in them lead to developmental disorders and disease conditions.

scholarly journals Chromosome orientation

2007 ◽  
Vol 179 (2) ◽  
pp. 179-181 ◽  
Author(s):  
Duane A. Compton
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Spindle Apparatus ◽  
Molecular Machinery

Precise chromosome segregation during cell division results from the attachment of chromosomes to microtubules emanating from both poles of the spindle apparatus. The molecular machinery involved in establishing and maintaining properly oriented microtubule attachments remains murky. Some clarity is now emerging with the identification of Bod1 (Biorientation Defective 1), a protein that promotes chromosome biorientation by unleashing chromosomes from improperly oriented microtubule attachments.

scholarly journals Role of centrosomal adaptor proteins of the TACC family in the regulation of microtubule dynamics during mitotic cell division

2013 ◽  
Vol 394 (11) ◽  
pp. 1411-1423 ◽  
Author(s):  
Harish C. Thakur ◽  
Madhurendra Singh ◽  
Luitgard Nagel-Steger ◽  
Daniel Prumbaum ◽  
Eyad Kalawy Fansa ◽  
...  
Keyword(s):  
Cell Division ◽  
Mitotic Spindle ◽  
Protein Complexes ◽  
Coiled Coil ◽  
Adaptor Proteins ◽  
Mitotic Cell ◽  
Microtubule Dynamics ◽  
Aurora A Kinase ◽  
Spindle Apparatus

Abstract During the mitotic division cycle, cells pass through an extensive microtubule rearrangement process where microtubules forming the mitotic spindle apparatus are dynamically instable. Several centrosomal- and microtubule-associated proteins are involved in the regulation of microtubule dynamics and stability during mitosis. Here, we focus on members of the transforming acidic coiled coil (TACC) family of centrosomal adaptor proteins, in particular TACC3, in which their subcellular localization at the mitotic spindle apparatus is controlled by Aurora-A kinase-mediated phosphorylation. At the effector level, several TACC-binding partners have been identified and characterized in greater detail, in particular, the microtubule polymerase XMAP215/ch-TOG/CKAP5 and clathrin heavy chain (CHC). We summarize the recent progress in the molecular understanding of these TACC3 protein complexes, which are crucial for proper mitotic spindle assembly and dynamics to prevent faulty cell division and aneuploidy. In this regard, the (patho)biological role of TACC3 in development and cancer will be discussed.

scholarly journals Loss of spatial control of the mitotic spindle apparatus in a Chlamydomonas reinhardtii mutant strain lacking basal bodies.

Genetics ◽  
1995 ◽  
Vol 141 (3) ◽  
pp. 945-960 ◽  
Author(s):  
L L Ehler ◽  
J A Holmes ◽  
S K Dutcher
Keyword(s):  
Cell Division ◽  
Chlamydomonas Reinhardtii ◽  
Mitotic Spindle ◽  
Basal Bodies ◽  
Cleavage Furrow ◽  
Wild Type ◽  
Spindle Positioning ◽  
Spindle Apparatus ◽  
Variable Distribution ◽  
Spindle Position

Abstract The bld2-1 mutation in the green alga Chlamydomonas reinhardtii is the only known mutation that results in the loss of centrioles/basal bodies and the loss of coordination between spindle position and cleavage furrow position during cell division. Based on several different assays, bld2-1 cells lack basal bodies in > 99% of cells. The stereotypical cytoskeletal morphology and precise positioning of the cleavage furrow observed in wild-type cells is disrupted in bld2-1 cells. The positions of the mitotic spindle and of the cleavage furrow are not correlated with respect to each other or with a specific cellular landmark during cell division in bld2-1 cells. Actin has a variable distribution during mitosis in bld2-1 cells, but this aberrant distribution is not correlated with the spindle positioning defect. In both wild-type and bld2-1 cells, the position of the cleavage furrow is coincident with a specialized set of microtubules found in green algae known as the rootlet microtubules. We propose that the rootlet microtubules perform the functions of astral microtubules and that functional centrioles are necessary for the organization of the cytoskeletal superstructure critical for correct spindle and cleavage furrow placement in Chlamydomonas.

scholarly journals The mitotic crosslinking protein PRC1 acts as a mechanical dashpot to resist microtubule sliding

2019 ◽  
Author(s):  
Ignas Gaska ◽  
Mason Armstrong ◽  
April Alfieri ◽  
Scott Forth
Keyword(s):  
Cell Division ◽  
Optical Tweezers ◽  
Motor Proteins ◽  
Sliding Velocity ◽  
Spindle Apparatus ◽  
Motor Activities ◽  
Frictional Forces ◽  
Slow Motions ◽  
Resistive Forces ◽  
Minimal Resistance

AbstractCell division in eukaryotes requires the regulated assembly of the spindle apparatus. The proper organization of microtubules within the spindle is driven by motor proteins that exert forces to push and slide filaments, while non-motor proteins can crosslink filaments into higher order motifs such as overlapping bundles. It has not been clear how active and passive forces are integrated to produce regulated mechanical outputs within spindles. Here we employ a combined optical tweezers and TIRF microscopy instrument to directly measure the resistive forces produced by the mitotic crosslinking protein PRC1. We observe that PRC1 generates frictional forces that resist microtubule sliding. These forces scale with microtubule sliding velocity and the number of PRC1 crosslinks, but do not depend on overlap length or PRC1 density within overlaps. Our results suggest that PRC1 ensembles act like a mechanical dashpot, producing significant resistance against fast motions, but minimal resistance against slow motions, allowing for the integration of diverse motor activities into a single mechanical outcome.

The Ultrastructure of the Nuclear Events of Binary Fission in Paramecium bursaria and the Effects of Colchicine on Cell Division

1974 ◽  
Vol 32 ◽  
pp. 276-277
Author(s):  
L. M. Lewis
Keyword(s):  
Cell Division ◽  
Nuclear Envelope ◽  
Condensed Chromatin ◽  
Binary Fission ◽  
Paramecium Bursaria ◽  
Nuclear Events ◽  
Division Axis

The effects of colchicine on extranuclear microtubules associated with the macronucleus of Paramecium bursaria were studied to determine the possible role that these microtubules play in controlling the shape of the macronucleus. In the course of this study, the ultrastructure of the nuclear events of binary fission in control cells was also studied.During interphase in control cells, the micronucleus contains randomly distributed clumps of condensed chromatin and microtubular fragments. Throughout mitosis the nuclear envelope remains intact. During micronuclear prophase, cup-shaped microfilamentous structures appear that are filled with condensing chromatin. Microtubules are also present and are parallel to the division axis.

Stimulated Virus Production in Vinblastine and Cytochalasin-Induced Multinucleate Cells

1970 ◽  
Vol 28 ◽  
pp. 186-187
Author(s):  
Krishan Awtar
Keyword(s):  
Cell Division ◽  
Normal Cell ◽  
Virus Production ◽  
Multinucleate Cells ◽  
Daughter Cells ◽  
Cell Divisions ◽  
Nuclear Membranes ◽  
Division 2 ◽  
Vinblastine Sulfate

Exposure of cells to low sublethal but mitosis-arresting doses of vinblastine sulfate (Velban) results in the initial arrest of cells in mitosis followed by their subsequent return to an “interphase“-like stage. A large number of these cells reform their nuclear membranes and form large multimicronucleated cells, some containing as many as 25 or more micronuclei (1). Formation of large multinucleate cells is also caused by cytochalasin, by causing the fusion of daughter cells at the end of an otherwise .normal cell division (2). By the repetition of this process through subsequent cell divisions, large cells with 6 or more nuclei are formed.

Birefringence and Ultrastructure of Isolated, Stabilized Spindles

1976 ◽  
Vol 34 ◽  
pp. 64-65
Author(s):  
James R. LaFountain ◽  
Robert L. Evans
Keyword(s):  
Fiber Birefringence ◽  
Spindle Apparatus

Previous investigations on the spindle apparatus in primary spermatocytes of the crane fly, Nephrotoma suturalis, with polarizing optics have shown that chromosomal fibers can be detected as positively birefringent bands extending from the chromosomes to the poles (1). Chromosomal fiber birefringence reaches a maximum at metaphase when five distinct fibers can be seen in each half spindle. An obvious question raised by these results was what is the ultrastructural basis of birefringence?Initial attempts to characterize the ultrastructure of crane-fly spindles showed that there were hundreds of microtubules (MTs) in these spindles, but there was no evidence that they were distributed in a pattern that corresponded to the pattern of birefringence (2,3).

Confocal microscopy of the cytoskeleton in living plant cells following microinjection of fluorescent probes

1993 ◽  
Vol 51 ◽  
pp. 130-131
Author(s):  
Ann Cleary
Keyword(s):  
Cell Division ◽  
Fluorescent Probes ◽  
Actin Filaments ◽  
Intracellular Transport ◽  
Cell Structure ◽  
Plant Cells ◽  
Cell Plate ◽  
Cell Cortex ◽  
Living Plant ◽  
Rhodamine Phalloidin

Microinjection of fluorescent probes into living plant cells reveals new aspects of cell structure and function. Microtubules and actin filaments are dynamic components of the cytoskeleton and are involved in cell growth, division and intracellular transport. To date, cytoskeletal probes used in microinjection studies have included rhodamine-phalloidin for labelling actin filaments and fluorescently labelled animal tubulin for incorporation into microtubules. From a recent study of Tradescantia stamen hair cells it appears that actin may have a role in defining the plane of cell division. Unlike microtubules, actin is present in the cell cortex and delimits the division site throughout mitosis. Herein, I shall describe actin, its arrangement and putative role in cell plate placement, in another material, living cells of Tradescantia leaf epidermis.The epidermis is peeled from the abaxial surface of young leaves usually without disruption to cytoplasmic streaming or cell division. The peel is stuck to the base of a well slide using 0.1% polyethylenimine and bathed in a solution of 1% mannitol +/− 1 mM probenecid.

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