Asymmetric cytokinesis guide the development of pseudomonads inRhynchospora pubera(Cyperaceae)

2013 ◽  
Vol 37 (3) ◽  
pp. 203-212 ◽  
Author(s):  
Juca Abramo Barrera San Martin ◽  
Celia Guadalupe Tardeli de Jesus Andrade ◽  
Alexandra Antunes Mastroberti ◽  
Jorge Ernesto de Araújo Mariath ◽  
André Luís Laforga Vanzela
Keyword(s):  
Asymmetric Cytokinesis

scholarly journals Two Related Subpellicular Cytoskeleton-associated Proteins inTrypanosoma brucei Stabilize Microtubules

2002 ◽  
Vol 13 (3) ◽  
pp. 1058-1070 ◽  
Author(s):  
Cécile Vedrenne ◽  
Christiane Giroud ◽  
Derrick R. Robinson ◽  
Sébastien Besteiro ◽  
Christophe Bosc ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Molecular Weight ◽  
Trypanosoma Brucei ◽  
Cold Resistance ◽  
Chinese Hamster ◽  
Low Molecular Weight ◽  
Microtubule Bundle ◽  
Microtubule Associated Proteins ◽  
Associated Proteins ◽  
Asymmetric Cytokinesis

The subpellicular microtubules of the trypanosome cytoskeleton are cross-linked to each other and the plasma membrane, creating a cage-like structure. We have isolated, from Trypanosoma brucei, two related low-molecular-weight cytoskeleton-associated proteins (15- and 17-kDa), called CAP15 and CAP17, which are differentially expressed during the life cycle. Immunolabeling shows a corset-like colocalization of both CAPs and tubulin. Western blot and electron microscope analyses show CAP15 and CAP17 labeling on detergent-extracted cytoskeletons. However, the localization of both proteins is restricted to the anterior, microtubule minus, and less dynamic half of the corset. CAP15 and CAP17 share properties of microtubule-associated proteins when expressed in heterologous cells (Chinese hamster ovary and HeLa), colocalization with their microtubules, induction of microtubule bundle formation, cold resistance, and insensitivity to nocodazole. When overexpressed inT. brucei, both CAP15 and CAP17 cover the whole subpellicular corset and induce morphological disorders, cell cycle-based abnormalities, and subsequent asymmetric cytokinesis.

scholarly journals SKAP2 regulates Arp2/3 complex for actin-mediated asymmetric cytokinesis by interacting with WAVE2 in mouse oocytes

Cell Cycle ◽  
2017 ◽  
Vol 16 (23) ◽  
pp. 2272-2281
Author(s):  
Shu-Wen He ◽  
Bai-Hui Xu ◽  
Yu Liu ◽  
Ya-Long Wang ◽  
Ming-Huang Chen ◽  
...  
Keyword(s):  
Mouse Oocytes ◽  
Asymmetric Cytokinesis

WHAMM is required for meiotic spindle migration and asymmetric cytokinesis in mouse oocytes

2012 ◽  
Vol 139 (4) ◽  
pp. 525-534 ◽  
Author(s):  
Xin Huang ◽  
Lu Ding ◽  
Rui Pan ◽  
Peng-Fei Ma ◽  
Pan-Pan Cheng ◽  
...  
Keyword(s):  
Meiotic Spindle ◽  
Mouse Oocytes ◽  
Asymmetric Cytokinesis

Mitosis in primary cultures ofDrosophila melanogasterlarval neuroblasts

2002 ◽  
Vol 115 (15) ◽  
pp. 3061-3072 ◽  
Author(s):  
Matthew S. Savoian ◽  
Conly L. Rieder
Keyword(s):  
Primary Cultures ◽  
Short Term ◽  
Metaphase Chromosomes ◽  
Simple Method ◽  
Spindle Poles ◽  
Spindle Midzone ◽  
Anaphase B ◽  
Bipolar Spindles ◽  
Multi Mode ◽  
Asymmetric Cytokinesis

Although Drosophila larval neuroblasts are routinely used to define mutations affecting mitosis, the dynamics of karyokinesis in this system remain to be described. Here we outline a simple method for the short-term culturing of neuroblasts, from Drosophila third instar larvae, that allows mitosis to be followed by high-resolution multi-mode light microscopy. At 24°C, spindle formation takes 7±0.5 minutes. Analysis of neuroblasts containing various GFP-tagged proteins (e.g. histone,fizzy, fizzy-related and α-tubulin) reveals that attaching kinetochores exhibit sudden, rapid pole-directed motions and that congressing and metaphase chromosomes do not undergo oscillations. By metaphase, the arms of longer chromosomes can be resolved as two chromatids, and they often extend towards a pole. Anaphase A and B occur concurrently, and during anaphase A chromatids move poleward at 3.2±0.1 μm/minute, whereas during anaphase B the spindle poles separate at 1.6±01 μm/minute. In larger neuroblasts,the spindle undergoes a sudden shift in position during midanaphase, after which the centrally located centrosome preferentially generates a robust aster and stops moving, even while the spindle continues to elongate. Together these two processes contribute to an asymmetric positioning of the spindle midzone,which, in turn, results in an asymmetric cytokinesis. Bipolar spindles form predominately (83%) in association with the separating centrosomes. However,in 17% of the cells, secondary spindles form around chromosomes without respect to centrosome position: in most cases these spindles coalesce with the primary spindle by anaphase, but in a few they remain separate and define additional ectopic poles.

scholarly journals Planar Spindle Orientation and Asymmetric Cytokinesis in the Mouse Small Intestine

2007 ◽  
Vol 55 (11) ◽  
pp. 1173-1180 ◽  
Author(s):  
Elizabeth S. Fleming ◽  
Mark Zajac ◽  
Darcy M. Moschenross ◽  
David C. Montrose ◽  
Daniel W. Rosenberg ◽  
...  
Keyword(s):  
Small Intestine ◽  
Spindle Orientation ◽  
Mouse Small Intestine ◽  
Asymmetric Cytokinesis

Enucleation of Human Erythroblasts Is a Process of Asymmetric Cytokinesis.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1663-1663
Author(s):  
Miwa Hebiguchi ◽  
Makoto Hirokawa ◽  
Yong-Mei Guo ◽  
Yoshinari Kawabata ◽  
Atsushi Komatsuda ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Ex Vivo ◽  
Experimental System ◽  
Band 3 ◽  
Integral Membrane Proteins ◽  
Differential Interference Contrast Microscopy ◽  
Hematopoietic Stem ◽  
Cell Culture Insert ◽  
Positive Nucleus ◽  
Asymmetric Cytokinesis

Abstract Background. During erythroblast enucleation, nuclei surrounded by plasma membrane separate from erythroblast cytoplasm. Enucleation has been thought to be a process similar to cytokinesis. However, more concrete evidence has been difficult to obtain because of a lack of an ex vivo experimental system capable of confirming cytokinesis. Focusing on the mechanism of cell division, we investigated the redistribution of cytoplasmic proteins and integral membrane proteins during enucleation, using ex vivo generation system of mature human blood cells from hematopoietic stem cells. Materials and Methods. The highly purified human CD34+ cells were grown in the presence of interleukin-3, stem cell factor and erythropoietin (EPO) in a liquid phase. After 7 days of culture, the generated cells (day 7 cells) were replaced in a medium with EPO alone. The cells matured and terminally differentiated into reticulocytes during a 13–15-day culture period. We mainly used non-gravity and non-pipetting system to avoid physical stress that may disrupt the connection between the nucleus and reticulocyte. Day 9 cells, predominantly consisted of polychromatophilic erythroblasts and expressed glycophorin A (GPA) at a purity of 97%, were labeled with DNA-staining dye SYTO21 for the direct monitoring of the enucleation process, using differential interference contrast microscopy. We also cultured day 9 cells until day 14, on 4-well culture slides or on the membrane of a cell culture insert system, and removed culture medium by aspiration without centrifugation and pipetting. The day 14 cells on the slide were analyzed using immunohistochemical staining, whereas the cells on the membrane were embedded in O.C.T. compound for confocal microscopy. Results. Approximately a half of erythroblasts enucleated until day 14. The monitoring of the enucleation process at day 13 showed autonomous extrusion of SYTO21 positive nucleus from single erythroblast. Some of the expelled nuclei were still connected with reticulocyte through strings that were positive for antibody against tubulin, actin, GPA, band 3 and glycophorin C (GPC). The expelled nuclei were covered by lamin, a protein specific for nuclear membrane, which were surrounded by a substance positive for GPA, band 3, GPC, p55, 4.1R80, actin, tubulin, b-spectrin, calnexin and cytochrome C, although the distribution of each proteins were asymmetric between nuclei and reticulocytes. An intense area of GPA, GPC, band 3, 4.1R80, actin, tubulin, myosin and b-spectrin was found in the region of the constriction between the extruding nucleus and incipient reticulocyte in enucleating cells. In cells just before enucleation, tubulin and actin formed a radial array around the nucleus. The center of the radial array was positive for centrin and NuMA, indicating that the cenriole formation occurred during an enucleation process. Conclusion. Our investigations show that a part of human erythroblasts enucleate independent of an interaction with accessory cells. The appearance of cenriole and the asymmetric redistribution of cytoplasmic and integral membrane proteins during enucleation strongly suggest that enucleation of human erythroblasts is a process of asymmetric cytokinesis.

A Role for Survivin in Enucleation of Erythroid Progenitors.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1704-1704
Author(s):  
Ganesan Keerthivasan ◽  
Jeong Ah. Kang ◽  
Dwight S. Seferos ◽  
Chad A. Mirkin ◽  
Amittha Wickrema ◽  
...  
Keyword(s):  
Caspase 3 ◽  
Survivin Expression ◽  
Underlying Mechanism ◽  
Erythroid Progenitors ◽  
Chromosomal Segregation ◽  
Erythroleukemia Cells ◽  
Chromosomal Passenger ◽  
Murine Erythroleukemia ◽  
Asymmetric Cytokinesis ◽  
Murine Erythroleukemia Cells

Abstract Enucleation is the final step in the development of reticulocytes and this process is unique to mammalian red blood cells among vertebrates. Even though enucleation of erythroblasts was structurally studied by electron microscopy half a century ago, little is known about the underlying mechanism. Initially it was thought that enucleation involved degradation of DNA and other apoptotic processes. More recently it has been shown that enucleation of erythroid progenitors does not require major apoptotic machinery including caspase-3 activation (Krauss et al, 2005; Yoshida et al, 2005). Alternatively, it has been suggested that enucleation in erythroblasts is a result of asymmetric cytokinesis. In support of this later model, survivin, a regulator of chromosomal segregation and cytokinesis, which also has an anti apoptotic role, is highly expressed in orthochromatic erythroblasts, cells at the stage of differentiation just prior to enucleation (Gurbuxani et al, 2005). Moreover conditional heterozygous deletion of survivin in hematopoietic cells caused a decrease in enucleated cells in the spleen (Leung et al, 2007). This has led us to hypothesize that survivin has a role in enucleation of erythroblasts. To test this prediction, we first over expressed survivin in MEL (murine erythroleukemia) cells and then subjected them to DMSO induced differentiation. Normally MEL cells decrease their survivin expression level upon differentiation and at the same time undergo limited enucleation (<4%) even after 5 days of differentiation. In contrast, survivin overexpressing clones consistently enucleated 3–5 fold more than control cells, suggesting that levels of survivin are likely to be important for enucleation. We are currently harnessing the power of survivin antisense nanoparticle agents to assess the specific requirement of survivin in enucleation of primary human orthochromatic erythroblasts. Separately, we evaluated the localization of survivin and its known partners in enucleating primary human erythroid cells by confocal microscopy. Survivin is predominantly localized to the cytoplasmic compartment and to our surprise did not colocalize with Aurora B kinase and INCENP, two of its partners in the chromosomal passenger complex, which is essential for mitosis. On the contrary, we noticed that survivin partially colocalized with actin at the junction between the extruding nucleus and cytoplasm, as well as in the periphery of cytoplasm in these enucleating cells. Moreover enucleation assays performed in the presence of various inhibitors of cell cycle and cytokinesis did not prevent enucleation in erythroblasts. Taken together, these findings demonstrate that enucleation is not a form of cytokinesis and further suggest that survivin participates in enucleation by a novel mechanism.

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