Three-dimensional structure of the lipovitellin–phosvitin complex from amphibian oocytes

Ohlendorf, D.H.; Wrenn, Richard F.; Banaszak, Leonard J.

doi:10.1038/272028a0

Cited by 52 publications

(14 citation statements)

References 20 publications

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“…After analyzing Fourier transforms of a series of electron micrographs of negatively stained crystalline fragments from X . Zaeuis, Ohlendorf et al (1978) concluded that the crystals represent a n orthorhombic array of lipoprotein complexes. Each complex, in turn, consists of two subunits that most likely are not identical (Lange et al, 1983).…”

Section: Vitellogenesismentioning

confidence: 99%

Ultrastructural aspects of oogenesis and oocyte growth in fish and amphibians

Wallace

Selman

1990

J. Elec. Microsc. Tech.

234

152

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Oogenesis, the early events of primary oocyte growth (meiotic arrest, synapsis, ribosomal gene duplication), and folliculogenesis can be seen to particular advantage in the germinal ridge of the syngnathan ovary. After budding off the germinal ridge (a compartment of the luminal epithelium), nascent follicles then enter into a linear array of developing follicles within which temporal and stage-specific events can be correlated with spatial distribution. Prominent features of the later phase of primary oocyte growth include intense transcriptional activity and the formation and subsequent dispersal of the Balbiani vitelline body (mitochondrial cloud) concomitant with an increase in cytoplasmic organelles and volume. Further oocyte growth is characterized by a period of cortical alveolus (in teleosts) or cortical granule (in anurans) formation, in which Golgi elements play a predominant role, and finally vitellogenesis. The latter process, which is responsible for the preponderance of oocyte growth, includes the hepatic synthesis and secretion of vitellogenin (VTG), the uptake of VTG from the bloodstream into the oocyte by receptor-mediated endocytosis, and the transport of VTG via endosomes and multivesicular bodies to forming yolk platelets. In the process, VTG is proteolytically cleaved into the yolk proteins, which assume either a monoclinic (in cyclostomes) or orthorhombic (in teleosts and amphibians) crystalline array. Other structures associated with the growing oocyte are also briefly discussed, including nuage, the vitelline envelope, intercellular junctions between the oocyte and overlying follicle cells, pigment, intramitochondrial crystals in ranidae, and annulate lamellae.

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Section: Vitellogenesismentioning

confidence: 99%

Ultrastructural aspects of oogenesis and oocyte growth in fish and amphibians

Wallace

Selman

1990

J. Elec. Microsc. Tech.

234

152

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“…As Martin & Lee (1976) reported, there are indications th at our crystals are lipoprotein, and these unit cell dimensions are consistent with the dimensions of protein molecules. References to artificially grown lipoprotein crystals are very scarce, but naturally occurring crystals of lipoprotein in frog eggs have been reported and a low resolution structure determined (Ohlendorf et al 1978).…”

Section: Resultsmentioning

confidence: 99%

Structural studies on crystals found in the intestine of Nematodirus battus

Lee

Nixon

North

1980

Proc. R. Soc. Lond. B.

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“…Secondly, it is also applicable to macromolecular structure determination by electron microscopy of stained microcrystals. Since the crystalline projections which we have imaged have been shown to provide basically sound representations of the (known) crystal structure, it follows that three-dimensional reconstructions synthesized from such projections (Ohlendorf et al, 1978) can be used to define accurately those portions of the unit cell occupied by protein. Filtered projection images might also be of use in the early stages of an X-ray structural analysis of an unknown protein (Shelley & McPherson, 1980).…”

Section: Discussionmentioning

confidence: 99%

Specificity of stain distribution in electron micrographs of protein molecules contrasted with uranyl acetate

Steven

Navia

1982

Journal of Microscopy

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The mechanism of contrast enhancement of protein molecules by negative staining with uranyl acetate has been investigated by analysing electron micrographs of microcrystals of the human immunoglobulin Dob. Digitally filtered micrographs were compared systematically with idealized reference images which were constructed computationally, starting from knowledge of the primary sequence and three-dimensional crystal structure of this IgG molecule. By separately modelling negative staining as bulk exclusion of heavy metals, and positive staining as the specific decoration of charged amino acid residues, and then combining these simulated images, we were able to assess quantitatively the amount of positive staining present in micrographs of ostensibly 'negativelfstained' proteins. At a resolution of 2 nm, we find that the experimental images do indeed exhibit predominantly negative staining, the best matches being obtained by simulations which also include a minor contribution (1040%) of positive staining. We have also compared two independent measures for the significant resolution present in images of periodic biological specimens : (i) the outermost visible orders of optical diffraction patterns, and (ii) the band-limited resolutions of the idealized simulations when they most closely match the experimental images. These criteria observe close correspondence, thus vindicating the traditional practice of inferring resolution from the optical diffraction spectra of indirectly represented (stained) objects.

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Three-dimensional structure of the lipovitellin–phosvitin complex from amphibian oocytes

Cited by 52 publications

References 20 publications

Ultrastructural aspects of oogenesis and oocyte growth in fish and amphibians

Ultrastructural aspects of oogenesis and oocyte growth in fish and amphibians

Structural studies on crystals found in the intestine of Nematodirus battus

Specificity of stain distribution in electron micrographs of protein molecules contrasted with uranyl acetate

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