Immunological localization of the major architectural protein associated with the nuclear envelope of the Xenopus laevis oocyte

1982 ◽  
Vol 138 (2) ◽  
pp. 319-330 ◽  
Author(s):  
Reimer Stick ◽  
Georg Krohne
Keyword(s):  
Xenopus Laevis ◽  
Nuclear Envelope ◽  
Xenopus Laevis Oocyte ◽  
Architectural Protein

scholarly journals Involvement of single-stranded tails in homologous recombination of DNA injected into Xenopus laevis oocyte nuclei.

1991 ◽  
Vol 11 (6) ◽  
pp. 3268-3277 ◽  
Author(s):  
E Maryon ◽  
D Carroll
Keyword(s):  
Homologous Recombination ◽  
Xenopus Laevis ◽  
Gel Electrophoresis ◽  
Xenopus Laevis Oocyte ◽  
Molecular Models ◽  
Mixed Substrates ◽  
Two Dimensional Gel Electrophoresis ◽  
Recombination Pathway ◽  
Made In

Homologous recombination of DNA molecules injected into Xenopus laevis oocyte nuclei is extremely efficient when those molecules are linear and have overlapping homologous ends. It was previously shown that a 5'----3' exonuclease activity in oocytes attacks injected linear DNAs and leaves them with single-stranded 3' tails. We tested the hypothesis that such tailed molecules are early intermediates on the pathway to recombination products. Substrates with 3' tails were made in vitro and injected into oocytes, where they recombined rapidly and efficiently. In experiments with mixed substrates, molecules with 3' tails entered recombination intermediates and products more rapidly than did molecules with flush ends. Molecules endowed in vitro with 5' tails also recombined efficiently in oocytes, but their rate was not faster than for flush-ended substrates. In most cases, the 5' tails served as templates for resynthesis of the 3' strands, regenerating duplex ends which then entered the normal recombination pathway. In oocytes from one animal, some of the 5' tails were removed, and this was exacerbated when resynthesis was partially blocked. Analysis by two-dimensional gel electrophoresis of recombination intermediates from 5'-tailed substrates confirmed that they had acquired 3' tails as a result of the action of the 5'----3' exonuclease. These results demonstrate that homologous recombination in oocytes proceeds via a pathway that involves single-stranded 3' tails. Molecular models incorporating this feature are discussed.

Imaging of Xenopus laevis Oocyte Plasma Membrane in Physiological-Like Conditions by Atomic Force Microscopy

2013 ◽  
Vol 19 (5) ◽  
pp. 1358-1363 ◽  
Author(s):  
Massimo Santacroce ◽  
Federica Daniele ◽  
Andrea Cremona ◽  
Diletta Scaccabarozzi ◽  
Michela Castagna ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Plasma Membrane ◽  
High Resolution ◽  
Membrane Proteins ◽  
Xenopus Laevis ◽  
Functional Study ◽  
Xenopus Laevis Oocyte ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging

AbstractXenopus laevis oocytes are an interesting model for the study of many developmental mechanisms because of their dimensions and the ease with which they can be manipulated. In addition, they are widely employed systems for the expression and functional study of heterologous proteins, which can be expressed with high efficiency on their plasma membrane. Here we applied atomic force microscopy (AFM) to the study of the plasma membrane of X. laevis oocytes. In particular, we developed and optimized a new sample preparation protocol, based on the purification of plasma membranes by ultracentrifugation on a sucrose gradient, to perform a high-resolution AFM imaging of X. laevis oocyte plasma membrane in physiological-like conditions. Reproducible AFM topographs allowed visualization and dimensional characterization of membrane patches, whose height corresponds to a single lipid bilayer, as well as the presence of nanometer structures embedded in the plasma membrane and identified as native membrane proteins. The described method appears to be an applicable tool for performing high-resolution AFM imaging of X. laevis oocyte plasma membrane in a physiological-like environment, thus opening promising perspectives for studying in situ cloned membrane proteins of relevant biomedical/pharmacological interest expressed in this biological system.

scholarly journals Correlation between structure and mass distribution of the nuclear pore complex and of distinct pore complex components.

1990 ◽  
Vol 110 (4) ◽  
pp. 883-894 ◽  
Author(s):  
R Reichelt ◽  
A Holzenburg ◽  
E L Buhle ◽  
M Jarnik ◽  
A Engel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Nuclear Envelope ◽  
Three Dimensional ◽  
Structural Features ◽  
Nuclear Pore ◽  
Xenopus Laevis Oocyte ◽  
Three Dimensional Model ◽  
Transmission Electron ◽  
Freeze Dried

Nuclear pore complexes (NPCs) prepared from Xenopus laevis oocyte nuclear envelopes were studied in "intact" form (i.e., unexposed to detergent) and after detergent treatment by a combination of conventional transmission electron microscopy (CTEM) and quantitative scanning transmission electron microscopy (STEM). In correlation-averaged CTEM pictures of negatively stained intact NPCs and of distinct NPC components (i.e., "rings," "spoke" complexes, and "plug-spoke" complexes), several fine structural features arranged with octagonal symmetry about a central axis could reproducibly be identified. STEM micrographs of unstained/freeze-dried intact NPCs as well as of their components yielded comparable but less distinct features. Mass determination by STEM revealed the following molecular masses: intact NPC with plug, 124 +/- 11 MD; intact NPC without plug, 112 +/- 11 MD; heavy ring, 32 +/- 5 MD; light ring, 21 +/- 4 MD; plug-spoke complex, 66 +/- 8 MD; and spoke complex, 52 +/- 3 MD. Based on these combined CTEM and STEM data, a three-dimensional model of the NPC exhibiting eightfold centrosymmetry about an axis perpendicular to the plane of the nuclear envelope but asymmetric along this axis is proposed. This structural polarity of the NPC across the nuclear envelope is in accord with its well-documented functional polarity facilitating mediated nucleocytoplasmic exchange of molecules and particles.

scholarly journals The mRNA encoding a β subunit of heterotrimeric GTP-binding proteins is localized to the animal pole of Xenopus laevis oocyte and embryos

1996 ◽  
Vol 59 (2) ◽  
pp. 141-151 ◽  
Author(s):  
Eric Devic ◽  
Laurent Paquereau ◽  
Karine Rizzoti ◽  
Armelle Monier ◽  
Bernard Knibiehler ◽  
...  
Keyword(s):  
Xenopus Laevis ◽  
Binding Proteins ◽  
Xenopus Laevis Oocyte ◽  
Β Subunit ◽  
Animal Pole ◽  
Gtp Binding Proteins ◽  
Gtp Binding

Metaphase protein phosphorylation in Xenopus laevis eggs

1987 ◽  
Vol 7 (2) ◽  
pp. 760-768
Author(s):  
M J Lohka ◽  
J L Kyes ◽  
J L Maller
Keyword(s):  
Xenopus Laevis ◽  
Nuclear Envelope ◽  
Protein Phosphorylation ◽  
Tyrosine Kinases ◽  
Chromosome Condensation ◽  
Nuclear Envelope Breakdown ◽  
M Phase ◽  
Nuclear Events ◽  
Gamma S

Cytoplasmic extracts of metaphase (M-phase)-arrested Xenopus laevis eggs support nuclear envelope breakdown and chromosome condensation in vitro. Induction of nuclear breakdown is inhibited by AMPP(NH)P, a nonhydrolyzable ATP analog, but not by ATP or gamma-S-ATP, a hydrolyzable ATP analog, suggesting that protein phosphorylation may be required for M-phase nuclear events in vitro. By addition of [gamma-32P]ATP, we have identified in cytoplasmic extracts and in intact eggs at least six phosphoproteins that are present during M-phase but absent in G1/S-phase. These phosphoproteins also appear in response to partially purified preparations of maturation-promoting factor. A subset of these proteins are thiophosphorylated by gamma-S-ATP under conditions that promote nuclear envelope breakdown and chromosome condensation. Each of these proteins is phosphorylated on serine and threonine, and one, a 42-kilodalton protein, is also phosphorylated on tyrosine both in extracts and in intact eggs. These results indicate that activation of protein kinases accounts for at least part of the increased phosphorylation in M-phase and that both protein-serine-threonine kinases and protein-tyrosine kinases may play a role in controlling M-phase nuclear behavior.

scholarly journals Nuclear hourglass technique: An approach that detects electrically open nuclear pores in Xenopus laevis oocyte

1999 ◽  
Vol 96 (23) ◽  
pp. 13530-13535 ◽  
Author(s):  
T. Danker ◽  
H. Schillers ◽  
J. Storck ◽  
V. Shahin ◽  
B. Kramer ◽  
...  
Keyword(s):  
Xenopus Laevis ◽  
Xenopus Laevis Oocyte ◽  
Nuclear Pores

Formation of branched DNA structures by Xenopus laevis oocyte extract

Nature ◽  
1977 ◽  
Vol 270 (5639) ◽  
pp. 754-756 ◽  
Author(s):  
DOMENICA GANDINI ATTARDI ◽  
EMILIO MATTOCCIA ◽  
GLAUCO P. TOCCHINI-VALENTINI
Keyword(s):  
Xenopus Laevis ◽  
Xenopus Laevis Oocyte ◽  
Dna Structures ◽  
Branched Dna

scholarly journals Xenopus laevis oocytes infected with multi-drug–resistant bacteria: implications for electrical recordings

2011 ◽  
Vol 138 (2) ◽  
pp. 271-277 ◽  
Author(s):  
Denice O'Connell ◽  
Karen Mruk ◽  
Jessica M. Rocheleau ◽  
William R. Kobertz
Keyword(s):  
Xenopus Laevis ◽  
Mammalian Cells ◽  
Resistant Bacteria ◽  
Xenopus Laevis Oocytes ◽  
Xenopus Laevis Oocyte ◽  
Drug Resistant ◽  
Animal Pole ◽  
Antibiotic Cocktail ◽  
Storage Media ◽  
Drug Resistant Bacteria

The Xenopus laevis oocyte has been the workhorse for the investigation of ion transport proteins. These large cells have spawned a multitude of novel techniques that are unfathomable in mammalian cells, yet the fickleness of the oocyte has driven many researchers to use other membrane protein expression systems. Here, we show that some colonies of Xenopus laevis are infected with three multi-drug–resistant bacteria: Pseudomonas fluorescens, Pseudomonas putida, and Stenotrophomonas maltophilia. Oocytes extracted from infected frogs quickly (3–4 d) develop multiple black foci on the animal pole, similar to microinjection scars, which render the extracted eggs useless for electrical recordings. Although multi-drug resistant, the bacteria were susceptible to amikacin and ciprofloxacin in growth assays. Supplementing the oocyte storage media with these two antibiotics prevented the appearance of the black foci and afforded oocytes suitable for whole-cell recordings. Given that P. fluorescens associated with X. laevis has become rapidly drug resistant, it is imperative that researchers store the extracted oocytes in the antibiotic cocktail and not treat the animals harboring the multi-drug–resistant bacteria.

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