Decision of Spindle Poles and Division Plane by Double Preprophase Bands in a BY-2 Cell Line Expressing GFP–Tubulin

The first cell division in zygotes of the fucoid brown alga Pelvetia compressa is asymmetric and we are interested in the mechanism controlling the alignment of this division. Since the division plane bisects the mitotic apparatus, we investigated the timing and mechanism of spindle alignments. Centrosomes, which give rise to spindle poles, aligned with the growth axis in two phases – a premetaphase rotation of the nucleus and centrosomes followed by a postmetaphase alignment that coincided with the separation of the mitotic spindle poles during anaphase and telophase. The roles of the cytoskeleton and cell cortex in the two phases of alignment were analyzed by treatment with pharmacological agents. Treatments that disrupted cytoskeleton or perturbed cortical adhesions inhibited pre-metaphase alignment and we propose that this rotational alignment is effected by microtubules anchored at cortical adhesion sites. Postmetaphase alignment was not affected by any of the treatments tested, and may be dependent on asymmetric cell morphology.

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Control of division plane in normal and griseofulvin-treated microsporocytes of Magnolia

Journal of Cell Science ◽

10.1242/jcs.103.4.1031 ◽

1992 ◽

Vol 103 (4) ◽

pp. 1031-1038 ◽

Cited By ~ 2

Author(s):

R.C. Brown ◽

B.E. Lemmon

Keyword(s):

Cell Plate ◽

Equatorial Region ◽

Cell Periphery ◽

Drug Induced ◽

Spatial Control ◽

Division Plane ◽

Spindle Poles ◽

Wall Deposition ◽

A Cell ◽

Multiple Poles

Meiotic cytokinesis in microsporocytes of Magnolia is an unusual form of the simultaneous type; phragmoplast expansion is not accompanied by a cell plate, wall deposition is centripetal, and infurrowing of the cytoplasm after first meiosis results in semicells connected by an isthmus. Dyad domains are further defined by interaction of extensive radial systems of microtubules emanating from the daughter nuclei and by a band of organelles polarized in the equatorial region. After second meiosis, phragmoplasts are organized in the interzonal regions between the sister nuclei in each semicell and also at the interfaces of microtubules forming secondary interzonals between non-sister nuclei. Wall deposition is not initiated until after phragmoplasts expand to the cell periphery and fuse in the isthmus. Centripetal wall deposition in boundaries of spore domains marked by radial arrays of microtubules results in simultaneous quadripartitioning of the microsporocyte into a tetrad of microspores. Treatment of microsporocytes with griseofulvin resulted in atypically placed nuclei and supernumerary nuclei. Abnormalities could be traced to displaced spindles and to spindles with multiple poles. Drug-induced multinucleate coenocytes were able to organize microtubules and initiate cytokinesis in altered patterns. The data suggest that spindle alignment and aggregation of spindle poles are two components of spatial control that are operative in determining the normal arrangement of nuclei, and that the final placement of walls is a function of the postmeiotic nuclear-based radial arrays of microtubules which define spore domains.

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High Frequencies of Preprophase Bands in Soybean Protoplast Cultures

Journal of Cell Science ◽

10.1242/jcs.92.4.575 ◽

1989 ◽

Vol 92 (4) ◽

pp. 575-580

Author(s):

HONG WANG ◽

ADRIAN J. CUTLER ◽

LARRY C. FOWKE

Keyword(s):

Cell Line ◽

High Frequency ◽

Developmental Stages ◽

Plant Cells ◽

Experimental System ◽

Nuclear Surface ◽

High Frequencies ◽

Index Ratio ◽

Soybean Cell ◽

Preprophase Bands

Protoplasts derived from a non- regenerable soybean cell line provide an excellent experimental system for studying plant preprophase bands (PPBs). Cultured protoplasts developed PPBs in high frequencies, permitting a detailed analysis of PPB development. From observations of thousands of PPBs, six distinct developmental stages were identified. This classification should prove useful in recognizing developmental stages of PPBs and in comparing results among different tissues and species. Perinuclear fluorescence appeared when PPBs were well developed. It consisted of microtubule strands radiating from the nuclear surface at its early stages and more extensive arrays on the surface at later stages. All protoplast cultures from 0.5 day to 5 days had a PPB index (ratio between number of PPBs and number of phragmoplasts) greater than unity, suggesting that in this cell line a high frequency of PPBs is apparently not related to the potential for organized growth (e.g. embryogenesis). Different methods of quantifying the occurrence of PPBs were evaluated. The PPB value (ratio between % of cells with PPB and the mitotic index) was compared with the PPB index and results indicate that it is a useful new parameter for studies of the distribution of PPBs in plant cells.

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Use of abnormal preprophase bands to decipher division plane determination

Journal of Cell Science ◽

10.1242/jcs.114.3.599 ◽

2001 ◽

Vol 114 (3) ◽

pp. 599-607 ◽

Cited By ~ 2

Author(s):

C. Granger ◽

R. Cyr

Keyword(s):

Actin Filaments ◽

Fluorescent Protein ◽

Dominant Role ◽

Preprophase Band ◽

Cell Cortex ◽

Reporter Protein ◽

Division Plane ◽

Green Fluorescent ◽

Vacuolated Cells ◽

Preprophase Bands

Many premitotic plant cells possess a cortical preprophase band of microtubules and actin filaments that encircles the nucleus. In vacuolated cells, the preprophase band is visibly connected to the nucleus by a cytoplasmic raft of actin filaments and microtubules termed the phragmosome. Typically, the location of the preprophase band and phragmosome corresponds to, and thus is thought to influence, the location of the cell division plane. To better understand the function of the preprophase band and phragmosome in orienting division, we used a green fluorescent protein-based microtubule reporter protein to observe mitosis in living tobacco bright yellow 2 cells possessing unusual preprophase bands. Observations of mitosis in these unusual cells support the involvement of the preprophase band/phragmosome in properly positioning the preprophase nucleus, influencing spindle orientation such that the cytokinetic phragmoplast initially grows in an appropriate direction, and delineating a region in the cell cortex that attracts microtubules and directs later stages of phragmoplast growth. Thus, the preprophase band/phragmosome appears to perform several interrelated functions to orient the division plane. However, functional information associated with the preprophase band is not always used or needed and there appears to be an age or distance-dependent character to the information. Cells treated with the anti-actin drug, latrunculin B, are still able to position the preprophase nucleus suggesting that microtubules may play a dominant role in premitotic positioning. Furthermore, in treated cells, spindle location and phragmoplast insertion are frequently abnormal suggesting that actin plays a significant role in nuclear anchoring and phragmoplast guidance. Thus, the microtubule and actin components of the preprophase band/phragmosome execute complementary activities to ensure proper orientation of the division plane.

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

Development ◽

10.1242/dev.102.1.211 ◽

1988 ◽

Vol 102 (1) ◽

pp. 211-221 ◽

Cited By ~ 4

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.

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Ultrastructure of NPC/HK1 cells heterotransplanted in athymic nude mice

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010005384x ◽

1982 ◽

Vol 40 ◽

pp. 236-237

Author(s):

E.C. Chew ◽

C.L. Li ◽

D.P. Huang ◽

H.C. Ho ◽

L.S. Mak ◽

...

Keyword(s):

Cell Line ◽

Nude Mice ◽

Biopsy Specimen ◽

Epithelial Cell Line ◽

Present Communication ◽

Recurrent Tumour ◽

Athymic Nude Mice ◽

Cell Line Establishment ◽

Fine Structures ◽

Well Differentiated

An epithelial cell line, NPC/HK1, has recently been established from a biopsy specimen of a recurrent tumour of the nasopharynx which was histologically diagnosed as a moderately to well differentiated squamous cell carcinoma. A definite decrease in the amount of tonofilaments and desmosomes in the NPC/HK1 cells during the cell line establishment was observed. The present communication reports on the fine structures of the NPC/HK1 cells heterotraneplanted in athymic nude mice.

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Ultrastructure of Choriocarcinoma in Vitro

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010006372x ◽

1969 ◽

Vol 27 ◽

pp. 362-363

Author(s):

John C. Garancis ◽

R. A. Pattillo

Keyword(s):

Cell Line ◽

Physiological Function ◽

Cell System ◽

Bewo Cell ◽

Bewo Cells ◽

Gestational Choriocarcinoma ◽

Bewo Cell Line

Growth of cell system (BeWo-cell line) derived from human gestational choriocarcinoma has been established and continuously maintained in-vitro. Furthermore, it is evident from the previous studies that this cell line has retained the physiological function of the placental trophoblasts, namely the synthesis of human chorionic gonadotrophil(HCG).The BeWo cells were relatively small and possessed single nuclei, thus indicating that this cell line consists exclusively of cytotrophoblasts. In some instances cells appeared widely separated and their lateral surfaces were provided with numerous microvilli (Fig.1).

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An Established Epithelial Cell Line (NPC/HK1) from a Nasopharyngeal Carcinoma - II. A Sem Study

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053784 ◽

1982 ◽

Vol 40 ◽

pp. 224-225

Author(s):

Li C.L. ◽

Chew E.C. ◽

Huang D.P. ◽

Ho H.C. ◽

Mak L.S. ◽

...

Keyword(s):

Nasopharyngeal Carcinoma ◽

Epithelial Cell ◽

Surface Morphology ◽

Cell Line ◽

Epithelial Cell Line ◽

Present Communication ◽

Cells In Culture ◽

Sem Study ◽

Well Differentiated

An epithelial cell line, NPC/HK1, has recently been successfully established from a nasopharyngeal carcinoma of the moderately to well differentiated squamous type. The present communication reports on the surface morphology of the NPC/HK1 cells in culture.

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Aberrant Type C Virus Production in a Cell Line Derived from Balb/3T3

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100094693 ◽

1972 ◽

Vol 30 ◽

pp. 286-287

Author(s):

N. Savage ◽

A. Hackett

Keyword(s):

Electron Microscopy ◽

Cell Line ◽

Leukemia Virus ◽

Morphological Characteristics ◽

Virus Production ◽

Oncogenic Viruses ◽

Endogenous Virus ◽

Virus Particles ◽

Moloney Leukemia Virus ◽

A Cell

A cell line, UC1-B, which was derived from Balb/3T3 cells, maintains the same morphological characteristics of the non-transformed parental culture, and shows no evidence of spontaneous virus production. Survey by electron microscopy shows that the cell line consists of spindle-shaped cells with no unusual features and no endogenous virus particles.UC1-B cells respond to Moloney leukemia virus (MLV) infection by a change in morphology and growth pattern which is typical of cells transformed by sarcoma virus. Electron microscopy shows that the cells are now variable in shape (rounded, rhomboid, and spindle), and each cell type has some microvilli. Virtually all (90%) of the cells show virus particles developing at the cell surface and within the cytoplasm. Maturing viruses, typical of the oncogenic viruses, are found along with atypical tubular forms in the same cell.

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A New Human Breast Tumor Cell Line

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100115560 ◽

1975 ◽

Vol 33 ◽

pp. 388-389

Author(s):

R.E. Nordquist ◽

R.M. Wasik ◽

P.J. Riggs ◽

P.L. Munson ◽

F.B. Schafer

Keyword(s):

Electron Microscopy ◽

Cell Line ◽

Calf Serum ◽

Tumor Cell Line ◽

Electron Microscopic Examination ◽

Epithelial Cell Line ◽

Electron Microscopic ◽

Fixed Tissue ◽

Excised Tissue ◽

Caucasian Female

An infiltrating ductal cell carcinoma was removed from the breast of a postmenopausal Caucasian female. The excised tissue was divided into three parts; one part for electron microscopy, one part for tissue culture and the remainder frozen for immunological studies.The tissue for culture was minced finely with sterile razor blades and cultured in Falcon flasks containing Eagel's MEM supplemented with 10% heat denatured fetal calf serum. The tissue for electron microscopy was fixed in 6.25% glutaraldehyde in 0.1 M PO4 buffer plus 5% sucrose and postfixed in 1% OsO4 in the same buffer. The fixed tissue was dehydrated in graded ethanol and embedded in Spurr.The tissue which was cultured began to grow out after approximately six weeks and became a continuous epithelial cell line which was designated BOT-2 (Breast Original Tumor). Electron microscopic examination revealed that these cells had epithelial characteristics, i.e. the presence of tonofilaments and well formed desmosomes.

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