Microtubule and F-actin dynamics at the division site in living Tradescantia stamen hair cells

1992 ◽  
Vol 103 (4) ◽  
pp. 977-988 ◽  
Author(s):  
A.L. Cleary ◽  
B.E.S. Gunning ◽  
G.O. Wasteneys ◽  
P.K. Hepler
Keyword(s):  
Hair Cells ◽  
Preprophase Band ◽  
Cell Plate ◽  
Laser Scanning Microscopy ◽  
Actin Dynamics ◽  
Cell Cortex ◽  
Living Plant ◽  
Rhodamine Phalloidin ◽  
Division Site ◽  
The Future

We have visualised F-actin and microtubules in living Tradescantia virginiana stamen hair cells by confocal laser scanning microscopy after microinjecting rhodamine-phalloidin or carboxyfluorescein-labelled brain tubulin. We monitored these components of the cytoskeleton as the cells prepared for division at preprophase and progressed through mitosis to cytokinesis. Reorganisation of the interphase cortical cytoskeleton results in preprophase bands of both F-actin and microtubules that coexist in the cell cortex, centred on the site at which the future cell plate will fuse with the parent cell wall. The preprophase band of microtubules is formed from microtubules that polymerise and incorporate tubulin during prophase. The preprophase band of actin may form either by reorganisation of pre-existing filaments or by de novo polymerisation. Both cytoskeletal components disappear from the future division site approximately five minutes prior to the breakdown of the nuclear envelope. Cortical microtubules are undetectable throughout mitosis and cytokinesis, whereas cortical F-actin remains abundant, although it is notably excluded from the division site. The phragmoplast, containing both F-actin and microtubules, expands towards the cortical actin exclusion-zone through a region that has no detectable microtubules or F-actin. The phragmoplast comes to rest in the predefined region of the cortex that is devoid of F-actin. It is proposed that cortical F-actin may act as a “negative” template which could position the phragmoplast and cell plate correctly. This is the first in vivo documentation of F- actin dynamics at the division site in living plant cells.

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.

Quantification of microtubule dynamics in living plant cells using fluorescence redistribution after photobleaching

1994 ◽  
Vol 107 (4) ◽  
pp. 775-784 ◽  
Author(s):  
J.M. Hush ◽  
P. Wadsworth ◽  
D.A. Callaham ◽  
P.K. Hepler
Keyword(s):  
Mammalian Cells ◽  
Laser Scanning ◽  
Dynamic Instability ◽  
Animal Cell ◽  
Plant Cells ◽  
Preprophase Band ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Turnover Rates ◽  
Living Plant

Microtubule (MT) turnover within the four principal MT arrays, the cortical array, the preprophase band, the mitotic spindle and the phragmoplast, has been measured in living stamen hair cells of Tradescantia that have been injected with fluorescent neurotubulin. Using the combined techniques of confocal laser scanning microscopy and fluorescence redistribution after photobleaching (FRAP), we report that the half-time of turnover in spindle MTs is t 1/2 = 31 +/- 6 seconds, which is in excellent agreement with previous measurements of turnover in animal cell spindles. Tradescantia interphase MTs, however, exhibit turnover rates (t 1/2 = 67 +/- seconds) that are some 3.4-fold faster than those measured in interphase mammalian cells, and thus are revealed as being highly dynamic. Preprophase band and phragmoplast MTs have turnover rates similar to those of interphase MTs in Tradescantia. The spatial and temporal aspects of the fluorescence redistribution after photobleaching in all four MT arrays are more consistent with subunit exchange by the mechanism of dynamic instability than treadmilling. This is the first quantification of MT dynamics in plant cells.

Division Plane Establishment and Cytokinesis

2019 ◽  
Vol 70 (1) ◽  
pp. 239-267 ◽  
Author(s):  
Pantelis Livanos ◽  
Sabine Müller
Keyword(s):  
Secretory Pathway ◽  
Preprophase Band ◽  
Cell Plate ◽  
Division Plane ◽  
Spatial Reference ◽  
Division Site ◽  
Eukaryotic Proteins ◽  
Plate Formation ◽  
Membrane Compartment ◽  
Cytoplasmic Content

Plant cells divide their cytoplasmic content by forming a new membrane compartment, the cell plate, via a rerouting of the secretory pathway toward the division plane aided by a dynamic cytoskeletal apparatus known as the phragmoplast. The phragmoplast expands centrifugally and directs the cell plate to the preselected division site at the plasma membrane to fuse with the parental wall. The division site is transiently decorated by the cytoskeletal preprophase band in preprophase and prophase, whereas a number of proteins discovered over the last decade reside continuously at the division site and provide a lasting spatial reference for phragmoplast guidance. Recent studies of membrane fusion at the cell plate have revealed the contribution of functionally conserved eukaryotic proteins to distinct stages of cell plate biogenesis and emphasize the coupling of cell plate formation with phragmoplast expansion. Together with novel findings concerning preprophase band function and the setup of the division site, cytokinesis and its spatial control remain an open-ended field with outstanding and challenging questions to resolve.

Actin microfilaments are associated with the migrating nucleus and the cell cortex in the green alga Micrasterias. Studies on living cells

1994 ◽  
Vol 107 (7) ◽  
pp. 1929-1934 ◽  
Author(s):  
U. Meindl ◽  
D. Zhang ◽  
P.K. Hepler
Keyword(s):  
Laser Scanning ◽  
Nuclear Migration ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Cell Cortex ◽  
Actin Network ◽  
Cortical Actin ◽  
Electron Microscopic ◽  
Rhodamine Phalloidin ◽  
Growing Cell

Rhodamine-phalloidin or FITC-phalloidin has been injected in small amounts into living, developing cells of Micrasterias denticulata and the stained microfilaments visualized by confocal laser scanning microscopy. The results reveal that two different actin filament systems are present in a growing cell: a cortical actin network that covers the inner surface of the cell and is extended far into the tips of the lobes in both the growing and the nongrowing semicell; it is also associated with the surface of the chloroplast. The second actin system ensheathes the nucleus at the isthmus-facing side during nuclear migration. Its arrangement corresponds to that of the microtubule system that has been described in earlier electron microscopic investigations. The spatial correspondence between the distribution of actin filaments and microtubules suggests a cooperation between both cytoskeleton elements in generating the motive force for nuclear migration. The function of the cortical actin network is not yet clear. It may be involved in processes like transport and fusion of secretory vesicles and may also function in shaping and anchoring the chloroplast.

Structure of the cortical cytoskeleton in mammalian outer hair cells

1992 ◽  
Vol 102 (3) ◽  
pp. 569-580 ◽  
Author(s):  
M.C. Holley ◽  
F. Kalinec ◽  
B. Kachar
Keyword(s):  
Hair Cells ◽  
Structural Information ◽  
Outer Hair Cells ◽  
Cell Cortex ◽  
Rhodamine Phalloidin ◽  
Deoxyribonuclease I ◽  
Unit Structure ◽  
Cross Links ◽  
Elastic Responses ◽  
Discrete Domains

The cortical cytoskeletal lattice in outer hair cells is a two-dimensional actin-based structure, which can be labelled with rhodamine/phalloidin and disrupted by the enzyme deoxyribonuclease I. Structural information from thin sectioned, freeze-etched and negatively stained preparations shows that it is based upon two types of filament that form a cross-linked lattice of circumferential filaments. The cross-links are 70–80 nm long. Measurements of the spacing between circumferential filaments suggest that the lattice is stiffer circumferentially than it is longitudinally. Analysis of the orientation of circumferential filaments shows that it is composed of discrete domains of up to 10 microns 2. Relative movements between domains could allow substantial changes of cell shape without disrupting the unit structure of the lattice, thus allowing the cell cortex to retain its elastic responses to high-frequency deformations.

Relationship between preprophase band organization, F-actin and the division site in Allium

1990 ◽  
Vol 97 (2) ◽  
pp. 283-295
Author(s):  
Y. MINEYUKI ◽  
B. A. PALEVITZ
Keyword(s):  
Higher Plants ◽  
Preprophase Band ◽  
Cell Plate ◽  
Mitotic Apparatus ◽  
Division Plane ◽  
Division Site ◽  
Dividing Cells ◽  
G2 Phase

The preprophase band (PPB) of microtubules (Mts), which appears in the G2 phase of the cell cycle in higher plants but disappears well before the end of karyokinesis, is implicated in the determination of the division plane because its location marks the site at which the phragmoplast/cell plate will fuse with the parental plasmalemma during cytokinesis. The PPB first appears as a rather wide array, which progressively narrows before or during prophase. Actin-containing microfilaments (Mfs) have recently been reported in the PPB, but the role of these elements in PPB organization and/or function remains unclear. The present study employed fluorescence and pharmacological methods in symmetrically and asymmetrically dividing epidermal cells of Allium to probe this problem. Our results show that PPBs in cells treated with 2–200μM cytochalasin D (CD) are still transversely aligned but remain two to three times wider than mature bands in control cells. Treatment for 0.5 h at 20 μM is sufficient to make the PPBs abnormally widel Premitotic nuclear migration in asymmetrically dividing cells is also inhibited by CD, as is the positioning of the mitotic apparatus and the new cell plate. The plate is still transverse, however. Band-like arrays of cortical Mfs become evident in most interphase cells by prophase. The band remains quite wide compared to the final dimensions of the Mt PPB, and clearly encompasses it. Levels of CD as high as 200μM decrease the number of cells with transverse actin bands, although a majority still retain them. Other F-actin arrays are disrupted by the drug. Thus, while CD does not inhibit the formation of an initial, broad, transverse PPB in most cells, it does prevent the narrowing process that defines the precise division site. The role of actin in this effect is discussed.

A role for preprophase bands of microtubules in maturation of new cell walls, and a general proposal on the function of preprophase band sites in cell division in higher plants

1990 ◽  
Vol 97 (3) ◽  
pp. 527-537
Author(s):  
Y. MINEYUKI ◽  
B. E. S. GUNNING
Keyword(s):  
Cell Division ◽  
Hair Cells ◽  
Cell Walls ◽  
Higher Plants ◽  
Preprophase Band ◽  
Cell Plate ◽  
Time Lapse ◽  
Spatial Regulation ◽  
Plant Cell Division ◽  
Drug Treatments

Time-lapse video microscopy of dividing Tradescantia stamen hair cells that are undergoing cytokinesis has revealed that the maturation of the new cell wall is aided by factors at the site where the preprophase band of microtubules forms before mitosis. The wall changes from being fluid and wrinkled before it is inserted into the parental wall at the end of cytokinesis, to being stiff and flat by about 20 min after the time of attachment. This change occurs only if the new wall is inserted at the site formerly occupied by the preprophase band. The cell plate does not flatten when it is caused to insert elsewhere by drug treatments or by centrifugal displacement. If insertion at the correct site is delayed locally by centrifugation against the direction of expansion of the cell plate, then flattening is delayed at the same locality. In combination with a number of points from the literature of plant cell division, some of them very long-standing, our observations lead to a general proposal regarding the nature of the preprophase band site, its mode of action and timing of its operations, and how its role in spatial regulation of histogenesis is achieved.

The role of F-actin in determining the division plane of carrot suspension cells. Drug studies

Development ◽  
1988 ◽  
Vol 102 (1) ◽  
pp. 211-221 ◽  
Author(s):  
C.W. Lloyd ◽  
J.A. Traas
Keyword(s):  
Preprophase Band ◽  
Cell Plate ◽  
Suspension Cells ◽  
Mitotic Apparatus ◽  
Division Plane ◽  
Division Site ◽  
Cytoplasmic Actin ◽  
Spindle Poles ◽  
Extraction Buffer ◽  
Actin Cables

Following the report that a network of F-actin is associated with the nucleus throughout the division cycle, we have examined the involvement of F-actin in determining the division plane of carrot suspension cells. This was achieved by treating cells with drugs and then staining the unfixed cells with rhodaminyl lysine phallotoxin in detergent extraction buffer. In interphase, actin cables radiate from the nucleus but at the cortex become more or less transversely arranged in the pattern already known for cortical microtubules. Concentration of the cortical F-actin into a band at preprophase draws most of the nucleus- associated actin into a transvacuolar disc, thereby forming the phragmosome within which mitosis and cytokinesis occur. In addition to this transversely aligned structure, F-actin is also associated with the spindle poles during mitosis but these filaments tend to align at right angles to the phragmosomal actin. F-actin therefore defines transverse and longitudinal vectors as division approaches. Depolymerization of F-actin with cytochalasin D can cause the spindle axis to reorientate such that the pole-pole axis comes to lie, abnormally, parallel with the phragmosome. The cytokinetic apparatus (the phragmoplast) develops centrifugally within the phragmosome. There has been considerable speculation on the nature of the elements that guide the phragmoplast to the cortical site previously occupied by the preprophase band of microtubules. This study demonstrates that F-actin bridges the leading margin of the outgrowing phragmoplast to the opposing cortex. Radial actin strands therefore provide a ‘memory’ of the predetermined division plane whose perimeter had been marked at preprophase by a band composed of microtubules and F-actin. This relationship was perturbed with the herbicide, chloroisopropylphenyl carbamate. Preprophase bands of actin appear to form normally in herbicide-treated cells. However, cytokinesis does not occur within this predicted plane since the drug perturbs the mitotic spindle, forming three nuclei which become separated by Y-shaped, actin-containing phragmoplasts. Cytoplasmic actin strands connect the edges of the phragmoplast to the cortex. It is suggested that the irregular distribution of F-actin, which radiates from the herbicide-altered mitotic apparatus, provides alternative paths for outgrowth of the abnormal phragmoplasts. Caffeine is known to cause failure of cell plate formation. But apart from inducing cytoplasmic ‘starbursts’ of F-actin in interphase cells it does not appear to have any effect on F-actin-containing division structures. It is concluded that the formation of a transvacuolar phragmosome, spindle alignment and the ‘correct’ outgrowth of a planar cytokinetic apparatus to the predetermined boundary of the division site all involve F-actin.

scholarly journals Dynamic Apical-Basal Enrichment of the F-Actin during Cytokinesis in Arabidopsis Cells Embedded in Their Tissues

2021 ◽  
Author(s):  
Alexis Lebecq ◽  
Aurelie Fangain ◽  
Alice Boussaroque ◽  
Marie-Cecile Caillaud
Keyword(s):  
Cell Division ◽  
Tracking System ◽  
Preprophase Band ◽  
Cell Plate ◽  
Tumor Formation ◽  
Actin Dynamics ◽  
Root Cells ◽  
Developmental Defects ◽  
Plant Cell Division ◽  
Dividing Cells

During the life cycle of any multicellular organism, cell division contributes to the proliferation of the cell in the tissues as well as the generation of specialized cells, both necessary to form a functional organism. Therefore, the mechanisms of cell division need to be tightly regulated, as malfunctions in their control can lead to tumor formation or developmental defects. This is particularly true in land plants, where cells cannot relocate and therefore cytokinesis is key for morphogenesis. In the green lineage, cell division is executed in radically different manners than animals, with the appearance of new structures (the preprophase band (PPB), cytokinetic the cell plate and phragmoplast), and the disappearance of ancestral mechanisms (cleavage, centrosomes). While F-actin and microtubules closely co-exist to allow the orientation and the progression of the plant cell division, recent studies mainly focused on the involvement of microtubules in this key process. Here, we used our recently developed root tracking system to follow actin dynamics in dividing Arabidopsis meristematic root cells. In this study, we imaged in time and space the fluorescent-tagged F-actin reporter Lifeact together with cell division markers in dividing cells embedded in their tissues. In addition to the F-actin accumulation in the phragmoplasts, we observed and quantified a dynamic apical-basal enrichment of the F-actin during cytokinesis. The role and the possible actors responsible for F-actin dynamics during cytokinesis are discussed.

scholarly journals Actin dynamics coupled to clathrin-coated vesicle formation at the trans-Golgi network

2004 ◽  
Vol 165 (6) ◽  
pp. 781-788 ◽  
Author(s):  
Sebastien Carreno ◽  
Åsa E. Engqvist-Goldstein ◽  
Claire X. Zhang ◽  
Kent L. McDonald ◽  
David G. Drubin
Keyword(s):  
Time Lapse ◽  
Actin Dynamics ◽  
Coated Vesicle ◽  
Cell Cortex ◽  
Actin Assembly ◽  
Trans Golgi Network ◽  
Lysosome Biogenesis ◽  
Diverse Species ◽  
Golgi Network ◽  
Golgi Organization

In diverse species, actin assembly facilitates clathrin-coated vesicle (CCV) formation during endocytosis. This role might be an adaptation specific to the unique environment at the cell cortex, or it might be fundamental, facilitating CCV formation on different membranes. Proteins of the Sla2p/Hip1R family bind to actin and clathrin at endocytic sites in yeast and mammals. We hypothesized that Hip1R might also coordinate actin assembly with clathrin budding at the trans-Golgi network (TGN). Using deconvolution and time-lapse microscopy, we showed that Hip1R is present on CCVs emerging from the TGN. These vesicles contain the mannose 6-phosphate receptor involved in targeting proteins to the lysosome, and the actin nucleating Arp2/3 complex. Silencing of Hip1R expression by RNAi resulted in disruption of Golgi organization and accumulation of F-actin structures associated with CCVs on the TGN. Hip1R silencing and actin poisons slowed cathepsin D exit from the TGN. These studies establish roles for Hip1R and actin in CCV budding from the TGN for lysosome biogenesis.

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