Histone deacetylase activity is necessary for chromosome condensation during meiotic maturation in Xenopus laevis

2006 ◽  
Vol 14 (3) ◽  
pp. 319-332 ◽  
Author(s):  
Laura Magnaghi-Jaulin ◽  
Christian Jaulin
Keyword(s):  
Xenopus Laevis ◽  
Histone Deacetylase ◽  
Chromosome Condensation ◽  
Meiotic Maturation

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.

Phosphorylation and protein synthetic events in Xenopus laevis oocytes microinjected with pp60v-src

1985 ◽  
Vol 5 (12) ◽  
pp. 3629-3633
Author(s):  
J G Spivack ◽  
J L Maller
Keyword(s):  
Xenopus Laevis ◽  
Oocyte Maturation ◽  
Rous Sarcoma Virus ◽  
Actinomycin D ◽  
Meiotic Maturation ◽  
Xenopus Laevis Oocytes ◽  
Rous Sarcoma ◽  
Contrast Exposure ◽  
Sarcoma Virus ◽  
Qualitative Changes

Microinjection of purified pp60v-src, the transforming protein of Rous sarcoma virus, into Xenopus laevis oocytes accelerated the rate of progesterone- or insulin-induced meiotic maturation. This acceleration was abolished by incubating the oocytes with cycloheximide or puromycin during a 2-h interval between pp60v-src microinjection and progesterone addition. In contrast, exposure to actinomycin D did not alter the acceleration of maturation by microinjected pp60v-src. Associated with progesterone treatment and pp60v-src microinjection were a number of qualitative changes in phosphoproteins; a few of these changes are common to both stimuli. These results indicate that the action of pp60v-src in oocytes involves both phosphorylation and protein synthetic events that affect oocyte maturation.

Suppression of chromosome condensation during meiotic maturation induces parthenogenetic development of mouse oocytes

Development ◽  
1988 ◽  
Vol 104 (1) ◽  
pp. 97-103 ◽  
Author(s):  
H.J. Clarke ◽  
J. Rossant ◽  
Y. Masui
Keyword(s):  
Protein Synthesis ◽  
Blastocyst Stage ◽  
Chromosome Condensation ◽  
Meiotic Maturation ◽  
Dibutyryl Cyclic Amp ◽  
Developmental Arrest ◽  
Mouse Oocytes ◽  
Parthenogenetic Development ◽  
No Activation ◽  
Metaphase I

Mouse oocytes at metaphase I were treated with puromycin, which caused the chromosomes to become decondensed within an interphase nucleus. When the oocytes were allowed to resume protein synthesis, they returned to metaphase within 8–10 h and neither synthesized DNA nor cleaved, indicating that they had not been parthenogenetically activated by the puromycin treatment. However, when dibutyryl cyclic AMP was added to the medium after protein synthesis resumed, the oocytes remained in interphase. These oocytes maintained in interphase began DNA synthesis beginning 20 h after puromycin withdrawal, even though no activation stimulus had been given to them. After transfer to the oviducts of foster mothers, the oocytes could develop to the blastocyst stage. These results indicate that oocytes whose chromosomes were decondensed by puromycin treatment at metaphase I could begin parthenogenetic development in the absence of an activating stimulus, provided that they were prevented from returning to metaphase. In contrast, when the puromycin-treated oocytes were allowed to return to metaphase, they became developmentally arrested at the end of maturation. This suggests that the mechanism responsible for the developmental arrest of mature oocytes at metaphase II depends on cytoplasmic conditions that cause chromosome condensation to the metaphase state.

scholarly journals Identification and early activation of a Xenopus laevis p70s6k following progesterone-induced meiotic maturation.

1992 ◽  
Vol 11 (5) ◽  
pp. 1743-1749 ◽  
Author(s):  
H.A. Lane ◽  
S.J. Morley ◽  
M. Dorée ◽  
S.C. Kozma ◽  
G. Thomas
Keyword(s):  
Xenopus Laevis ◽  
Meiotic Maturation ◽  
Early Activation

scholarly journals A multiple subunit Mi-2 histone deacetylase from Xenopus laevis cofractionates with an associated Snf2 superfamily ATPase

1998 ◽  
Vol 8 (14) ◽  
pp. 843-848 ◽  
Author(s):  
Paul A. Wade ◽  
Peter L. Jones ◽  
Danielle Vermaak ◽  
Alan P. Wolffe
Keyword(s):  
Xenopus Laevis ◽  
Histone Deacetylase

scholarly journals Study of the structure and function of the HURP protein during mitotic division

2013 ◽  
Author(s):  
Κωνσταντίνος Νάκος
Keyword(s):  
Dna Binding ◽  
Xenopus Laevis ◽  
Histone Deacetylase ◽  
Dna Binding Protein ◽  
Mitotic Division ◽  
Structure And Function ◽  
Aurora A ◽  
Nucleosome Remodeling ◽  
And Function

Η πρωτεΐνη HURP (Hepatoma Up-Regulated protein) έχει αναγνωριστεί ως παράγονταςσυναρμολόγησης της ατράκτου (SAF) που ρυθμίζεται από τη RanGTP. Αρχικά βρέθηκε σε μιτωτικάεκχυλίσματα αυγών Xenopus laevis, σε σύμπλοκο με τις TPX2, XMAP215, Eg5 και Aurora A. Η HURPπροσδένεται στους μικροσωληνίσκους, εντοπίζεται κυρίως στους μικροσωληνίσκους των κινητοχώρωνκαι είναι απαραίτητη για την σωστή συναρμολόγηση της μιτωτικής ατράκτου. Παρόλο αυτά, πρωτεΐνεςπου αλληλεπιδρούν με τη HURP σε ανθρώπινα κύτταρα παραμένουν άγνωστες.Σε αυτή τη μελέτη περιγράφουμε την αναγνώριση μίας νέας πρωτεΐνης που αλληλεπιδρά με τη HURP,τη CHD4 (Chromodomain Helicase DNA binding protein 4) μία ATPάση της αναδιαμόρφωσης τηςχρωματίνης και καταλυτική υπομονάδα του συμπλόκου αποκετυλασών που ευθύνεται για τηναναδιαμόρφωση του νουκλεοσώματος (Nucleosome remodeling and histone Deacetylase - NuRD).Πρόσφατα η πρωτεΐνη CHD4 αναγνωρίστηκε ως πρωτεΐνη που προσδένεται στους μικροσωληνίσκουςκαι ρυθμίζεται από την RanGTP.Οι μελέτες μας σε ανθρώπινα κύτταρα έδειξαν ότι η CHD4 κατά τη μίτωση απελευθερώνεται από ταμιτωτικά χρωμοσώματα και εντοπίζεται στην άτρακτο, υποδεικνύοντας ένα καινούριο ρόλο της CHD4στη συναρμολόγηση της ατράκτου. Για να κατανοήσουμε τη λειτουργία της CHD4 πραγματοποιήσαμεμελέτες απαλοιφής της CHD4 με την τεχνική της αποσιώπισης γονιδίου με siRNA. Μείωση της CHD4προκαλεί βλάβες στη συναρμολόγηση της μιτωτικής ατράκτου και στη στοίχιση των χρωμοσωμάτωνστις αρχές της μίτωσης, οδηγώντας σε ανώμαλο διαχωρισμό των χρωμοσωμάτων. Επιπλέον, ηαπώλεια της CHD4 επηρρεάζει τη σταθερότητα των K-fibers μειώνοντας σημαντικά την ποσότητα των μικροσωληνίσκων των κινητοχώρων. Μετά την απαλοιφή της CHD4, ο εντοπισμός της HURP βρέθηκενα αλλάζει, χάνοντας την προτίμησή της για τους μικροσωληνίσκους, των κινητοχώρων,υποδεικνύοντας την πιθανή ρύθμιση του εντοπισμού της HURP από την CHD4. Τέλος από in vitro καιin vivo πειράματα, βρήκαμε ότι η CHD4 αλληλεπιδρά με τη μιτωτική κινάση Aurora A και την πρωτεΐνηTPX2 που συνδέεται με μικροσωληνίσκους, δημιουργώντας ένα καινούριο σύμπλοκο σημαντικό για τηλειτουργία της μιτωτικής ατράκτου στα κύτταρα θηλαστικών.

Downregulation of surface sodium pumps by endocytosis during meiotic maturation of Xenopus laevis oocytes

1990 ◽  
Vol 258 (1) ◽  
pp. C179-C184 ◽  
Author(s):  
G. Schmalzing ◽  
P. Eckard ◽  
S. Kroner ◽  
H. Passow
Keyword(s):  
Plasma Membrane ◽  
Xenopus Laevis ◽  
Sucrose Gradient ◽  
Plasma Membranes ◽  
Polyacrylamide Gel Electrophoresis ◽  
Buoyant Density ◽  
Sodium Dodecyl ◽  
Meiotic Maturation ◽  
Xenopus Laevis Oocytes ◽  
Sodium Pumps

During meiotic maturation, plasma membranes of Xenopus laevis oocytes completely lose the capacity to transport Na and K and to bind ouabain. To explore whether the downregulation might be due to an internalization of the sodium pump molecules, the intracellular binding of ouabain was determined. Selective permeabilization of the plasma membrane of mature oocytes (eggs) by digitonin almost failed to disclose ouabain binding sites. However, when the eggs were additionally treated with 0.02% sodium dodecyl sulfate (SDS) to permeabilize inner membranes, all sodium pumps present before maturation were recovered. Phosphorylation by [gamma-32P]ATP combined with SDS-polyacrylamide gel electrophoresis (PAGE) and autoradiography showed that sodium pumps were greatly reduced in isolated plasma membranes of eggs. According to sucrose gradient fractionation, maturation induced a shift of sodium pumps from the plasma membrane fraction to membranes of lower buoyant density with a protein composition different from that of the plasma membrane. Endocytosed sodium pumps identified on the sucrose gradient from [3H]ouabain bound to the cell surface before maturation could be phosphorylated with inorganic [32P]phosphate. The findings suggest that downregulation of sodium pumps during maturation is brought about by translocation of surface sodium pumps to an intracellular compartment, presumably endosomes. This contrasts the mechanism of downregulation of Na-dependent cotransport systems, the activities of which are reduced as a consequence of a maturation-induced depolarization of the membrane without a removal of the corresponding transporter from the plasma membrane.

Gonadotropins and the timing of progesterone-induced meiotic maturation of Xenopus laevis oocytes

1985 ◽  
Vol 109 (1) ◽  
pp. 32-40 ◽  
Author(s):  
Michael J. LaMarca ◽  
Lynn M. Westphal ◽  
David A. Rein
Keyword(s):  
Xenopus Laevis ◽  
Meiotic Maturation ◽  
Xenopus Laevis Oocytes
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