The Ultrastructure of the Nuclear Envelope of Amphibian Oocytes: A Reinvestigation

Scheer, Ulrich

doi:10.1083/jcb.45.2.445

Cited by 29 publications

(7 citation statements)

References 36 publications

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“…In this context the central granule was visualized by many authors as representing a transitory or dynamic structure rather than a static one. The observation of an actinomycin D (AMD)-induced decrease in central granule frequency in negatively stained, isolated nuclear envelopes (Wunderlich, 1969;Scheer, 1970b) was consistent with such an interpretation. However, as the present study shows, a decrease in central granule frequency after AMD treatment can not be found in ultrathin sections.…”

Section: Introductionsupporting

confidence: 63%

“…First, they r epresent cellular systems which are known for their especially high efficiency in RNA synthesis (within one second the RNA is synthesized for about 6000 ribosomes in a Tetrahymena macronucleus, Leick and Anderson, 1970, and for about 300000 ribosomes in the nucleus of a rapidly growing Xenopus oocyte, and nucleocytoplasmic transport (Franke, 1970b;, and secondly, the former positive results of an AMD effect on central granule frequency were from these objects (Wunderlich, 1969;Scheer, 1970b).…”

Section: Resultsmentioning

confidence: 99%

“…This makes clear that the occurrence of this structure in the central part of the pore is independent of concomitant RNA synthesis and nucleocytoplasmic transport of RNA molecules. Therefore the interpretative views of central granule dynamics, which are based on earlier results reporting a decrease of central granule frequency in negatively stained isolated nuclear envelopes after a treatment with AMD (Wunderlich, 1969;Scheer, 1970b), have to be reconsidered.…”

Section: Discussionmentioning

confidence: 99%

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Actinomycin D and the central granules in the nuclear pore complex: Thin sectioning versus negative staining

1972

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Summary. Thin section electron microscopy of Actinomycin D treated Tetrahymena cells and amphibian oocytes (Xenopus laevis, Triturus aZpestris) reveal no reduction in the central granules in the nuclear pore complexes. Possible reasons for the diversity between these results and earlier observations using negatively stained isolated nuclear envelopes from the same objects are discussed. The results clearly show that the presence of central granules within the nuclear pores does neither depend on nuclear RNA synthesis nor does indicate nucleocytoplasmic RNA transport. This conclusion leads to a reconsideration of the nature of the central granule. The functioning of the central granule of the nuclear pore complexes is further discussed in connection with recent studies on the ultrastructure of various types of cisternal pores.

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Section: Introductionsupporting

confidence: 63%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Actinomycin D and the central granules in the nuclear pore complex: Thin sectioning versus negative staining

1972

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“…47Y59 The increase in RNA content in liver nuclear membranes of newborn animals can be attributed to increased synthesis, in particular of ribosomes which may remain attached to the membrane and/or to the amount of RNA trapped in the nuclear pores during its exit from the nucleus. 60 In fact, it has been shown that the amount of mRNA released from nuclei is higher in the newborn and decreases with age. 61 Instead, the DNA is lower in the newborn and this result can be tentatively explained by assuming either that DNA is more sensitive to DNase or that less chromatin is linked to the nuclear membrane in newborn animals.…”

Section: Nuclear Membrane Compositionmentioning

confidence: 99%

Effect of lipid composition on rat liver nuclear membrane fluidity

Albi

Tomassoni

Viola-Magni

1997

Cell Biochem. Funct.

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Nuclear membrane fluidity is measured in rat liver by use of the fluorescence anisotropy of two probes: diphenylhexatriene and its cationic derivative trimethylammonium-diphenylhexatriene. It has been shown that, in 2-month-old rat liver cells, the bilayer surface is less fluid than the hydrophobic core. The fluidity was higher in 6-day-old rat liver nuclei, in which both the amount of cholesterol and the cholesterol/phospholipid ratio decreased. The influence of the single phospholipids, and in particular of phosphatidylcholine, has been studied by increasing the phosphatidylcholine with a choline base exchange reaction in isolated nuclear membranes. After this reaction, the fluorescence anisotropy of the bilayer surface increased, whereas at the hydrophobic core it decreased. Analysis of fatty acid composition shows an increase of phosphatidylcholine unsaturated fatty acids. The results show that the fluidity of nuclear membranes changes in relation to the lipid content and to the fatty acid composition. The role of nuclear membrane fluidity in cell function is discussed.

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“…In addition, if there is a block in protein synthesis, c.6. by application c.f actinoniycin (Scheer, 1970), both RNA synthesis and transport are prevented, so that insufficient RNA accumulates at the pores to trigger their 'opening'. Since nuclear pores are involved in polysonie formation (Mephan & Lane, 1969), their abnormalities could also account for the great ribosome variability seen in dyserythropoietic cells.…”

Section: Dyseuythuopoiesis In Aplastic Atzaemiamentioning

confidence: 99%

The Ultrastructure of Dyserythropoiesis in Aplastic Anaemia

1975

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Electron microscopy of erythropoiesis in aplastic anaemia has demonstrated some unique features of dyserythropoiesis at the ultrastructural level, which contribute to understanding of the morphological features which are seen in the light microscope. The findings provide further evidence for the presence of qualitative defects in erythropoiesis in aplastic conditions. The alterations seen included bi- and multinucleated cells, intercellular bridges containing microtubules, internuclear chromatin bridges, irregular nuclear shapes, juxta-nuclear and peripheral cisternal structures, ringed sideroblasts, a diversity of intranuclear inclusions, nuclear clefts in both eu- and heterochromatin, and a variety of anomalies of the nuclear membrane. The significance of the occurrence of these anomalies in aplastic anaemia is considered and the role of the nuclear membrane and of endoplasmic reticulum in the pathogenesis of aplastic anaemia is discussed.

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The Ultrastructure of the Nuclear Envelope of Amphibian Oocytes: A Reinvestigation

Cited by 29 publications

References 36 publications

Actinomycin D and the central granules in the nuclear pore complex: Thin sectioning versus negative staining

Actinomycin D and the central granules in the nuclear pore complex: Thin sectioning versus negative staining

Effect of lipid composition on rat liver nuclear membrane fluidity

The Ultrastructure of Dyserythropoiesis in Aplastic Anaemia

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