O-linked N-acetylglucosaminyltransferase inhibition prevents G2/M transition in Xenopus laevis oocytes.
Full-grown Xenopus oocytes are arrested at the prophase of the first meiotic division in a G(2)-like state. Progesterone triggers meiotic resumption also called the G(2)/M transition. This event is characterized by germinal vesicle breakdown (GVBD) and by a burst in phosphorylation level that reflects activation of M-phase-promoting factor (MPF) and MAPK pathways. Besides phosphorylation and ubiquitin pathways, increasing evidence has suggested that the cytosolic and nucleus-specific O-GlcNAc glycosylation also contributes to cell cycle regulation. To investigate the relationship between O-GlcNAc and cell cycle, Xenopus oocyte, in which most of the M-phase regulators have been discovered, was used. Alloxan, an O-GlcNAc transferase inhibitor, blocked G(2)/M transition in a concentration-dependent manner. Alloxan prevented GVBD and both MPF and MAPK activations, either triggered by progesterone or by egg cytoplasm injection. The addition of detoxifying enzymes (SOD and catalase) did not rescue GVBD, indicating that the alloxan effect did not occur through reactive oxygen species production. These results were strengthened by the use of a benzoxazolinone derivative (XI), a new O-GlcNAc transferase inhibitor. Conversely, injection of O-(2-acetamido-2-deoxy-D-glucopyranosylidene)amino-N-phenylcarbamate, an O-GlcNAcase inhibitor, accelerated the maturation process. Glutamine:fructose-6-phosphate amidotransferase inhibitors, azaserine and 6-diazo-5-oxonorleucine, failed to prevent GVBD. Such a strategy appeared to be inefficient; indeed, UDP-GlcNAc assays in mature and immature oocytes revealed a constant pool of the nucleotide sugar. Finally, we observed that cyclin B2, the MPF regulatory subunit, was associated with an unknown O-GlcNAc partner. The present work underlines a crucial role for O-GlcNAc in G(2)/M transition and strongly suggests that its function is required for cell cycle regulation.
Dehennaut
Vanessa
V
Laboratoire de Régulation des Signaux de Division, EA 4020, Université des Sciences et Technologies de Lille, SN3, IFR147, 59655 Villeneuve d'Ascq, France.
Lefebvre
Tony
T
Sellier
Chantal
C
Leroy
Yves
Y
Gross
Benjamin
B
Walker
Suzanne
S
Cacan
René
R
Michalski
Jean-Claude
JC
Vilain
Jean-Pierre
JP
Bodart
Jean-François
JF
D000117:Acetylglucosamine / Q000378:metabolism; D000818:Animals; D002374:Catalase / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects / Q000502:physiology*; D019926:Cyclin B / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016195:G2 Phase / Q000187:drug effects / Q000502:physiology*; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D016200:Maturation-Promoting Factor / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D017351:N-Acetylglucosaminyltransferases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009865:Oocytes / Q000201:enzymology*; D010766:Phosphorylation / Q000187:drug effects; D011499:Protein Processing, Post-Translational / Q000187:drug effects / Q000502:physiology*; D021122:Protein Subunits / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism; D014982:Xenopus laevis
D019926:Cyclin B; D004791:Enzyme Inhibitors; D021122:Protein Subunits; D017382:Reactive Oxygen Species; D025801:Ubiquitin; D002374:Catalase; D013482:Superoxide Dismutase; D017351:N-Acetylglucosaminyltransferases; D016200:Maturation-Promoting Factor; D020929:Mitogen-Activated Protein Kinase Kinases; D000117:Acetylglucosamine