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.

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.

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.

Plant cytokinesis: a tale of membrane traffic and fusion

2015 ◽  
Vol 43 (1) ◽  
pp. 73-78 ◽  
Author(s):  
Gerd Jürgens ◽  
Misoon Park ◽  
Sandra Richter ◽  
Sonja Touihri ◽  
Cornelia Krause ◽  
...  
Keyword(s):  
Higher Plants ◽  
Membrane Vesicles ◽  
Cell Plate ◽  
Division Plane ◽  
Daughter Cells ◽  
Division Site ◽  
Plant Cytokinesis ◽  
M Phase ◽  
Golgi Network ◽  
Sm Protein

Cytokinesis separates the forming daughter cells. Higher plants have lost the ability to constrict the plasma membrane (PM) in the division plane. Instead, trans-Golgi network (TGN)-derived membrane vesicles are targeted to the centre of the division plane and generate, by homotypic fusion, the partitioning membrane named cell plate (CP). The CP expands in a centrifugal fashion until its margin fuses with the PM at the cortical division site. Mutant screens in Arabidopsis have identified a cytokinesis-specific syntaxin named KNOLLE and an interacting Sec1/Munc18 (SM) protein named KEULE both of which are required for vesicle fusion during cytokinesis. KNOLLE is only made during M-phase, targeted to the division plane and degraded in the vacuole at the end of cytokinesis. Here we address mechanisms of KNOLLE trafficking and interaction of KNOLLE with different soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein (SNAP) receptor (SNARE) partners and with SM-protein KEULE, ensuring membrane fusion in cytokinesis.

The Organization of the Cytoskeleton During Meiosis in Eggplant (Solanum Melongena (L.)): Microtubules and F-Actin are Both Necessary for Coordinated Meiotic Division

1989 ◽  
Vol 92 (4) ◽  
pp. 541-550 ◽  
Author(s):  
J. A. TRAAS ◽  
S. BURGAIN ◽  
R. DUMAS DE VAULX
Keyword(s):  
Higher Plants ◽  
Solanum Melongena ◽  
Preprophase Band ◽  
Male Meiosis ◽  
Animal Cells ◽  
Division Plane ◽  
Nucleation Sites ◽  
Division Process ◽  
Spatial Programming

Address for reprints Because two division planes form at right angles, male meiosis in higher plants provides striking examples of both division control and spatial programming. To investigate these processes we have stained microtubules and actin filaments during male meiosis in the eggplant. Our results indicate the following. (1) That microtubules and their nucleation sites are involved in the establishment of polarity; this is supported by our observation that the drug CIPC affects spindle polarity.(2) That actin microfilaments are involved in spindle formation and integrity, but not in the establishment of polarity: cytochalasin B and D affect the organization of the spindle microtubules, but not their polarized distribution.(3) That microtubules radiating from the daughter nuclei at the cell poles during interkinesis probably establish the future division plane by concentrating actin in that plane (cf. the proposed role of asters in positioning the contractile ring in animal cells).(4) That this concentration of F-actin in the division plane may be involved in preparing the cytoplasm for cytokinesis and in memorizing the division plane (much as the preprophase band observed in polarized tissues does).(5) That phragmoplast formation is a two-step process. No phragmoplast forms after metaphase I, but a four-way phragmoplast forms after metaphase II, indicating that mitosis and cytokinesis are not obligatorily coupled. These studies demonstrate that actin and microtubules are jointly involved in the spatial coordination of the division process.

The role of the cytoskeleton and associated proteins in determination of the plant cell division plane

2013 ◽  
Vol 75 (2) ◽  
pp. 258-269 ◽  
Author(s):  
Carolyn G. Rasmussen ◽  
Amanda J. Wright ◽  
Sabine Müller
Keyword(s):  
Cell Division ◽  
Plant Cell ◽  
Division Plane ◽  
Plant Cell Division ◽  
Associated Proteins ◽  
Cell Division Plane

scholarly journals Pollen Development in Orchids. 5. A Generative Cell Domain Involved in Spatial Control of the Hemispherical Cell Plate

1991 ◽  
Vol 100 (3) ◽  
pp. 559-565
Author(s):  
R. C. BROWN ◽  
B. E. LEMMON
Keyword(s):  
Generative Cell ◽  
Preprophase Band ◽  
Cell Plate ◽  
Generative Nucleus ◽  
Pollen Mitosis ◽  
Spatial Control ◽  
Division Plane ◽  
Radial System ◽  
Vegetative Pole ◽  
First Pollen Mitosis

The unequal first pollen mitosis in moth orchids (Phalaenopsis) is followed by an unusual form of cytokinesis that isolates a small lens-shaped generative cell from a large vegetative cell. No preprophase band of microtubules predicts the division plane and the new cell plate grows completely around the generative cell rather than fusing with the parental wall. Development of the phragmoplast cytoskeleton consisting of fusiform bundles of microtubules and F-actin occurs in three major stages: (1) the initial asymmetrical phragmoplast conforming to the shape of the interzonal region, which tapers from the broad mass of chromosomes at the generative pole to the rounded mass at the vegetative pole; (2) the symmetrical plate-like phragmoplast; and (3) the hemispherical phragmoplast, which curves around the generative nucleus. Microtubules of the generative half of the hemispherical phragmoplast are nuclearbased, while those on the vegetative side terminate in endoplasmic reticulum. The path of the phragmoplast appears to outline a cytoplasmic domain denned by a radial system of microtubules emanating from the generative nucleus.

scholarly journals TANGLED1 mediates interactions between microtubules that may promote spindle organization and phragmoplast guidance to the division site in maize

2019 ◽  
Author(s):  
Pablo Martinez ◽  
Ram Dixit ◽  
Rachappa S. Balkunde ◽  
Seán E. O’Leary ◽  
Kenneth A. Brakke ◽  
...  
Keyword(s):  
Critical Role ◽  
Preprophase Band ◽  
Microtubule Organization ◽  
Division Plane ◽  
Plane Orientation ◽  
Division Site ◽  
Structural Framework ◽  
Cell Shapes ◽  
Division Plane Orientation

AbstractThe microtubule cytoskeleton serves as a dynamic structural framework for mitosis in eukaryotic cells. TANGLED1 (TAN1) is a microtubule-binding protein that localizes to the division site and mitotic microtubules and plays a critical role in division plane orientation in plants. Here, in vitro experiments demonstrate that TAN1 directly binds microtubules, mediating microtubule zippering or end-on microtubule interactions, depending on their contact angle. Maize tan1 mutant cells improperly position the preprophase band (PPB), which predicts the future division site. However, cell-shape-based modeling indicates that PPB positioning defects are likely a consequence of abnormal cell shapes and not due to TAN1 absence. Spindle defects in the tan1 mutant suggest that TAN1-mediated microtubule zippering may contribute to metaphase spindle organization. In telophase, co-localization of growing microtubules ends from the phragmoplast with TAN1 at the division site suggests that TAN1 interacts with microtubule tips end-on. Together, our results suggest that TAN1 contributes to spindle and phragmoplast microtubule organization to ensure proper division plane orientation.

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