Perturbation of mammalian cell division. III. The topography and kinetics of extrusion subdivision

If mitotic-arrested, cold-stored HeLa cells are incubated at 37 degrees C a proportion of the population divides by an aberrant process which we have called subdivision by extrusion. This process has been studied by time-lapse photography and shown to differ from normal cleavage in several respects. The cell surface becomes more generally mobile and, instead of producing the precisely localized furrowing activity of cytokinesis, gives rise to multiple surface protrusions. These protrusions enlarge at the expense of the parent cell and develop into a cluster of small daughter cells (mini segregants). The surface structure of the cell, as seen by scanning electron microscopy, also changes; the microvilli characteristic of interphase, metaphase and cleaving HeLa cells are lost during extrusion and the cell surface becomes smooth. Extrusion activity is much more variable than division by cleavage in terms of both topography and kinetics, and in general takes longer to complete. Some cells in the cold-treated populations divide by mixtures of cleavage and extrusion or by cleavage alone. The relative numbers of cells dividing in different ways vary with the conditions of pretreatment and incubation of the mitotic cells. The greater the perturbation (e.g. longer cold storage), the greater the proportion of extruding rather than cleaving cells. Human diploid cells can also be induced to subdivide by extrusion. Possible mechanisms underlying the different types of division activity are discussed.

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THE TIME OF SYNTHESIS AND THE CONSERVATION OF MITOSIS-RELATED PROTEINS IN CULTURED HUMAN AMNION CELLS

The Journal of Cell Biology ◽

10.1083/jcb.34.1.97 ◽

1967 ◽

Vol 34 (1) ◽

pp. 97-110 ◽

Cited By ~ 43

Author(s):

Jesse E. Sisken ◽

Elaina Wilkes

Keyword(s):

Time Lapse ◽

Major Effect ◽

Human Amnion ◽

Daughter Cells ◽

Low Concentrations ◽

Associated Proteins ◽

A Cell ◽

Quantitative Analyses ◽

Related Proteins ◽

Kinetics Of

p-Fluorophenylalanine (PFPA), an analogue of phenylalanine which may be incorporated into proteins, increases the duration of mitosis. In the present experiments, based upon quantitative analyses of time-lapse cinemicrographic films, brief treatments of cells with PFPA are shown to affect the duration of metaphase in only those cells which enter division during or shortly after treatment. The offspring of cells with prolonged metaphases also tend to have prolonged metaphases. Analyses of the kinetics of the appearance of prolonged metaphases indicate that some protein specifically associated with mitosis is synthesized primarily during a period which corresponds closely to G2. The manner in which the defect is passed on to daughter cells indicates that the protein involved is conserved and reutilized by daughter cells for their subsequent divisions. Comparable experiments performed with low concentrations of puromycin indicate that the major effect of PFPA is due to its incorporation into protein rather than its ability to inhibit protein synthesis. The fact that puromycin-induced effects can also be passed on to daughter cells is interpreted to mean that cells make only specific amounts of some mitosis-associated proteins and that if a cell "inherits" a deficiency in such protein it is not able to compensate for the deficiency.

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Growth-driven displacement of protein aggregates along the cell length ensures partitioning to both daughter cells inCaulobacter crescentus

10.1101/436394 ◽

2018 ◽

Author(s):

Frederic D. Schramm ◽

Kristen Schroeder ◽

Jonatan Alvelid ◽

Ilaria Testa ◽

Kristina Jonas

Keyword(s):

Protein Quality ◽

Caulobacter Crescentus ◽

Protein Aggregates ◽

Time Lapse ◽

Daughter Cells ◽

Chaperone Dnak ◽

Kinetics Of ◽

Successive Division ◽

Moderate Stress

AbstractAll living cells must deal with protein aggregation, which can occur as a result of experiencing stress. In the bacteriaEscherichia coliandMycobacterium smegmatis, aggregates collect at the cell poles and are retained over consecutive cell divisions only in the daughter cell that inherits the old pole, resulting in aggregation-free progeny within a few generations. Here we have studied thein vivokinetics of aggregate formation and clearance following heat and antibiotic stress inCaulobacter crescentus, which divides by a pre-programmed asymmetric cell cycle. Unexpectedly, we find that aggregates do not preferentially collect at the cell poles, but form as multiple distributed foci throughout the cell volume. Time-lapse microscopy revealed that under moderate stress, the majority of protein aggregates are short-lived and rapidly dissolved by the major chaperone DnaK and the disaggregase ClpB. Severe stress or genetic perturbation of the protein quality machinery results in long-lived protein aggregates, which individual cells can only clear by passing on to their progeny. Importantly, these persistent aggregates are neither collected at the old pole over multiple generations nor inherited exclusively by the old pole-inheriting stalked cell, but instead are partitioned between both daughter cells during successive division events in the same ratio. Our data indicate that this symmetric mode of aggregate inheritance is driven by the elongation and division of the growing mother cell. In conclusion, our study revealed a new pattern of aggregate inheritance in bacteria.

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The absence of centrioles from spindle poles of rat kangaroo (PtK2) cells undergoing meiotic-like reduction division in vitro.

The Journal of Cell Biology ◽

10.1083/jcb.72.2.368 ◽

1977 ◽

Vol 72 (2) ◽

pp. 368-379 ◽

Cited By ~ 39

Author(s):

S Brenner ◽

A Branch ◽

S Meredith ◽

M W Berns

Keyword(s):

Electron Microscopy ◽

Light And Electron Microscopy ◽

Time Lapse ◽

Spindle Pole ◽

Reduction Division ◽

Daughter Cells ◽

Spindle Poles ◽

Spindle Apparatus ◽

Time Lapse Photography

Light and electron microscopy were used to study somatic cell reduction division occurring spontaneously in tetraploid populations of rat kangaroo Potorous tridactylis (PtK2) cells in vitro. Light microscopy coupled with time-lapse photography documented the pattern of reduction division which includes an anaphase-like movement of double chromatid chromosomes to opposite spindle poles followed by the organization of two separate metaphase plates and synchronous anaphase division to form four poles and four daughter nuclei. The resulting daughter cells were isolated and cloned, showing their viability, and karyotyped to determine their ploidy. Ultrastructural analysis of cells undergoing reduction consistently revealed two duplexes of centrioles (one at each of two spindle poles) and two spindle poles in each cell that lacked centrioles but with microtubules terminating in a pericentriolar-like cloud of material. These results suggest that the centriole is not essential for spindle pole formation and division and implicate the could region as a necessary component of the spindle apparatus.

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A Study of the Kinetics of Hyphal Extension and Branch Initiation of Fungal Mycelia

Microbiology ◽

10.1099/00221287-81-1-225 ◽

2000 ◽

Vol 81 (1) ◽

pp. 225-236 ◽

Cited By ~ 197

Author(s):

A. P. J. Trinci

Keyword(s):

Mycelial Growth ◽

Specific Growth ◽

Hyphal Growth ◽

Time Lapse ◽

Geotrichum Candidum ◽

Growth Unit ◽

Mucor Hiemalis ◽

Hyphal Length ◽

Kinetics Of ◽

Time Lapse Photography

Growth of Mucor hiemalis, Geotrichum candidum, Aspergillus nidulans, Neurospora crassa and Penicillium chrysogenum was studied by time lapse photography. The total hyphal length of the mycelium of each species increased at an exponential rate; in M. hiemalis exponential growth continued until the mycelium had a total hyphal length in excess of 10 mm. After spore germination there was an initial phase of discontinuous tip production followed by a phase of ‘continuous’ tip production. The hyphal length and number of tips possessed by a mycelium increased exponentially at approximately the same specific growth rate. The amplitude of the oscillations in the length of the hyphal growth unit of a mycelium decreased progressively during mycelial growth and eventually the growth unit attained a more or less constant value. The results support the hypothesis that mycelial growth involves the duplication of a ‘growth unit’ which consists of a tip and a certain mean length of hypha.

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