Mitotic apparatus-surface interaction and cell division

Rappaport, R.

doi:10.1080/01688170.1986.10510203

Cited by 7 publications

(2 citation statements)

References 25 publications

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“…There is known to be a close relationship between cytokinesis and microtubule organization in sea urchin eggs (5,6). In amphibian eggs, the whole removal or a partial isolation of the amphiaster (4) or its destruction by colchicine injection (7) at a precleavage stage results in the absence of furrow formation.…”

Section: Discussionmentioning

confidence: 99%

“…Studies on sea urchin eggs have revealed that formation of the cleavage furrow depends on the amphiaster (2, 10, see 5,6 for reviews). In amphibian eggs the dependence of furrowing in the animal hemisphere on the amphiaster and the diastema formed in its middle plane was shown by chemical and surgical treatments (4, 7, lo), but that in the vegetal hemisphere was not studied.…”

Section: Introductionmentioning

confidence: 99%

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Furrow Formation in the Vegetal Hemisphere of Xenopus Eggs

Kubota

Sakamoto

1993

Dev Growth Differ

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The mechanism of furrow formation in the vegetal hemisphere of amphibian eggs was studied using Xenopus eggs. Injection of colchicine into the eggs after the furrow tip had entered the vegetal hemisphere arrested the subsequent cleavage. The effect of impairing the continuity between the animal and vegetal hemispheres was examined by squeezing the equator of uncleaved eggs from both sides with the edges of coverslips. On gentle squeezing a shallow vegetal furrow was formed at the first cleavage, whereas on strong squeezing furrowing was arrested at the equator. The mechanism of furrow formation in the vegetal hemisphere of amphibian eggs is discussed on the basis of these findings.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Furrow Formation in the Vegetal Hemisphere of Xenopus Eggs

Kubota

Sakamoto

1993

Dev Growth Differ

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Myosin heavy chain dephosphorylation during cytokinesis in dividing sea urchin embryos

Larochelle

Epel

1993

Cell Motil. Cytoskeleton

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Myosin heavy chain (MHC) phosphorylation was examined throughout the period of first cleavage in developing sea urchin embryos. MHC was found to be phosphorylated in these cells and, furthermore, the relative state of myosin phosphorylation was found to decrease as cells progressed through cytokinesis. Following the completion of cytokinesis, the relative state of MHC phosphorylation returned to levels observed in precytokinesis cells. The above results were obtained with myosin immunoprecipitated from whole cell lysates. In order to specifically examine the phosphorylation state of MHC in the cleavage furrow, a protocol was developed for the isolation of intact contractile rings from dividing sea urchin embryos. MHC was immunoprecipitated from isolated contractile rings and the relative phosphorylation state of this MHC was compared with that of MHC isolated from whole cell lysates prepared at the same time. MHC from isolated contractile rings was found to be significantly less phosphorylated than total cellular MHC, suggesting a role for MHC dephosphorylation during cytokinesis.Q 1993 Wiley-Lis, Inc.

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Reversing cytoplasmic flow in nucleated, constricted sand dollar eggs

Rappaport¹,

Rappaport²

1988

J. Exp. Zool.

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The purpose of this investigation was to study the nature of the immediate response of the surface to the mitotic apparatus in sand dollar (Echinarachnius parma) eggs. The normal geometrical relationship was changed by snaring fertilized eggs between opposed, overlapping hooks and constricting the eggs to reshape them into two partial spheres joined by a constricted neck about 27 Fm in diameter. When both asters of the mitotic apparatus lay on the same side of the constriction, cytoplasm flowed out of the nucleated part across the constriction, beginning about 30 min before anticipated cleavage time. After the asters moved across the constriction, the direction reversed, and reversal usually occurred several times before cleavage (n = 18). The average time between beginning of flow in one direction and beginning of flow in the opposite direction was 7.7 min (n = 23). Cells were bisected and constricted to determine the role of the mitotic apparatus. Bisected cells with two asters behaved like constricted normal cells (n = 15). Cells with no mitotic apparatus developed no cytoplasmic flow (n = 11). In cells with one aster, flow most often occurred within ten min of anticipated cleavage time (n = 14). When whole constricted eggs were treated with Cytochalasin B at the minimum concentration that blocks cleavage in normal eggs (3 pg/ml), neither cytoplasmic flow nor cleavage occurred, although the mitotic apparatus developed normally.Cytoplasmic flow in constricted eggs in cleavage stages requires asters and functional actinassociated cytoskeleton. The results suggest that the asters cause an increase in tension in nearby surfaces.The idea that the role of the mitotic apparatus in cytokinesis of animal cells is confined to preliminary modification of regional surface properties was postulated in the last century by Biitschli (1876) and then by Ziegler in 1903. Later, demonstrations of the cell's ability to complete division despite removal of the mitotic apparatus (Yatsu, '12; Hiramoto, '56) led to general acceptance of the idea. The nature of the immediate effect of mitotic apparatus action on the surface can not be determined by simple observation, and two alternative mechanisms have been suggested. Lillie ('031, Wolpert ('601, Schroeder ('81), and White and Borisy ('83) proposed that the mitotic apparatus causes a decrease in tension or relaxation of the affected surface, while Biitschli (18761, Ziegler ('03), and many others have proposed that the mitotic apparatus causes an increase in tension or contraction in tfhe affected surface. Either response could lead to the organization of the filamentous contractile ring (Arnold, '68; Schroeder, '681, which, it is generally agreed, bisects the cell by constriction.Measurements of the changes in cytoplasmic stiffness that appear to accompany the cell cycle (Hiramoto, '63; Yoneda and Dan, '72) have not provided a basis for eliminating either of the hypothetical mechanisms. The understanding of the relation between the stiffness changes and cytokinesis is complic...

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Mitotic apparatus-surface interaction and cell division

Cited by 7 publications

References 25 publications

Furrow Formation in the Vegetal Hemisphere of Xenopus Eggs

Furrow Formation in the Vegetal Hemisphere of Xenopus Eggs

Myosin heavy chain dephosphorylation during cytokinesis in dividing sea urchin embryos

Reversing cytoplasmic flow in nucleated, constricted sand dollar eggs

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