Geometrical Relations of the Cleavage Stimulus in Flattened, Perforated Sea Urchin Eggs

Rappaport, R.

doi:10.1111/j.1440-169x.1968.tb00139.x

Cited by 36 publications

(4 citation statements)

References 11 publications

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“…In the absence of additional information on the nature or distribution of the signal, it has been impossible to rule out either of these models. However, the ability of a very small block placed between the spindle midzone and the cortex to inhibit furrowing in flattened echinoderm eggs seems inconsistent with the astral relaxation mechanism (17,18). This result would also not necessarily be predicted if furrow induction is the result of stimulatory signals emanating from the astral centers but is, instead, most consistent with a model in which the origin of the signal is the spindle midzone.…”

mentioning

confidence: 66%

Rappaport rules: Cleavage furrow induction in animal cells

Oegema

Mitchison

1997

Proc. Natl. Acad. Sci. U.S.A.

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mentioning

confidence: 66%

Rappaport rules: Cleavage furrow induction in animal cells

Oegema

Mitchison

1997

Proc. Natl. Acad. Sci. U.S.A.

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“…A perfect spatial coordination has been showrr between the cleavage furrow and the mitotic spindle with respect to the position and the orientation in amphibian eggs (6,7) and echinoderm eggs (5. 10, 11,12,13). Thus, one may feel convinced that the initiation site of SCWs is determined by the relative position of the nucleus within the cytoplasm.…”

Section: Introductionmentioning

confidence: 99%

Nuclear Involvement in Localization of the Initiation Site of Surface Contraction Waves in Xenopus Eggs

et al. 1989

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The initiation site of surface contraction waves (SCWs) was examined in fertilized, parthenogenetically activated and enucleated Xenopus eggs after either rotation through 90° off the vertical axis or injection of colchicine. In enucleated eggs, SCWs always started from a top site of the egg under all conditions examined. In fertilized or activated eggs, SCWs started, depending on the experimental conditions, from either the sperm entry point, the animal pole region located sideward or the top site of the egg. Histological examinations of fertilized and activated eggs revealed that the nucleus was in most cases positioned close to the initiation site of SCWs under various experimental conditions. It is suggested from these results that the egg cytoplasm has an intrinsic capability of causing the surface to generate SCWs, and that the nucleus is generally involved in localizing the initiation site of SCWs in fertilized or activated Xenopus eggs. A possible mechanism for localizing the initiation site of SCWs in Xenopus eggs is proposed.

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“…On the basis of studies in the past several decades, it is well established that the mitotic apparatus, which consists of the spindle and asters, plays the central role in both inducing and localizing the cell division furrow. In fact, it has been shown that the mitotic apparatus seems to emit signals for inducing the cell division furrow during the second half of the mitotic phase (Hiramoto 1956; Rappaport 1961, 1966, 1968, 1981; reviewed by White & Borisy 1983). However, it still remains uncertain which part of the mitotic apparatus, the spindle, asters or both, plays the most essential role in the induction and localization of the cell division furrow.…”

Section: Introductionmentioning

confidence: 99%

“…For example, Rappaport (1961) demonstrated that an extra cleavage furrow could be induced by placing two asters of different mitotic apparatus close to each other in a single torus‐shaped sand dollar egg, arguing against the necessity of the spindle for the induction of the cleavage furrow. Further, he performed a chain of studies (Rappaport & Ebstein 1965; Rappaport 1966, 1968, 1981, 1986, 1992; Rappaport & Rappaport 1983, 1987) and revealed that the more distantly the aster edge is positioned from the cortex, the less likely the cleavage furrow is induced, suggesting that signals released from astral edges may be involved in the induction of the contractile ring and the cleavage furrow in echinoderm eggs. Other researchers have also accumulated theoretical and experimental evidence for an essential role of asters and astral microtubules in the induction of the cleavage furrow in animal cells such as eggs and embryos (Hiramoto 1956; Dettlaff 1963; Schroeder 1981; Devore et al .…”

Section: Introductionmentioning

confidence: 99%

Asters play only a dispensable role in the induction of the cleavage furrow in the blastomeres of early Xenopus embryos

Sakaida

Inomata

Shinagawa³

2004

Dev Growth Differ

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Kuroda et al . (2001) of our laboratory have previously revealed that exposure of early Xenopus embryos to 150 m M urethane results in complete suppression of formation of the asters and the cleavage furrow, as well as significant reduction of the size of the spindle in the blastomeres, allowing only 1 or 2 cycles of mitosis but not cytokinesis. In the course of closer examination of the effect of urethane on the cleavage of blastomeres of early Xenopus embryos, we unexpectedly discovered that exposure of early Xenopus embryos to 75 m M urethane did not prevent cell division at all, though asters were not detected in the blastomeres. Instead, they contained a spindle that appeared rather normal. They also formed the diastema, a thin yolk-free structure, which is considered to play an essential role in the induction of the cleavage furrow. Essentially the same results were obtained in the exposure of embryos to vinblastine, a well-known microtubule inhibitor: exposure of embryos to 20 µg/mL vinblastine resulted in complete suppression of cleavage of the blastomeres, where formation of both the spindle and asters were perfectly suppressed. By contrast, exposure of embryos to 5 µg/mL vinblastine did not prevent cleavage in the blastomeres though asters were not detected, whereas the rather normal spindle was formed. Thus, there was a close correlation between the formation of the normal spindle, not asters, and that of the cell division furrow and the diastema in the blastomeres of early Xenopus embryos. We suggest that while the spindle plays an essential role, asters are likely to play only a dispensable role in the induction of the cleavage furrow in even very large cells like the blastomeres of early Xenopus embryos.

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Geometrical Relations of the Cleavage Stimulus in Flattened, Perforated Sea Urchin Eggs

Cited by 36 publications

References 11 publications

Rappaport rules: Cleavage furrow induction in animal cells

Rappaport rules: Cleavage furrow induction in animal cells

Nuclear Involvement in Localization of the Initiation Site of Surface Contraction Waves in Xenopus Eggs

Asters play only a dispensable role in the induction of the cleavage furrow in the blastomeres of early Xenopus embryos

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