The antibiotic azatyrosine suppresses progesterone or [Val12]p21 Ha-ras/insulin-like growth factor I-induced germinal vesicle breakdown and tyrosine phosphorylation of Xenopus mitogen-activated protein kinase in oocytes.
The antibiotic azatyrosine [DL-3-(5-hydroxy-2-pyridyl)alanine] suppressed meiotic maturation in oocytes induced by progesterone or the combination of [Val12]p21Ha-ras microinjection and insulin-like growth factor I. The suppression was dose-dependent in the range of 20-250 microM azatyrosine. In addition, azatyrosine blocked the tyrosine phosphorylation of Xp42, a member of the mitogen-activated protein kinase family, after progesterone or [Val12]p21Ha-ras/insulin-like growth factor I stimulation. Activation of maturation-promoting factor, as shown by a decrease in the tyrosine phosphorylation of the Xenopus homolog of p34cdc2, was also suppressed by azatyrosine. Azatyrosine had no effect in vivo or in vitro on the growth factor-induced autophosphorylation of the oocyte insulin-like growth factor I receptor. Azatyrosine has been shown by others [Shindo-Okada, N., Makabe, O., Nagahara, H. & Nishimura, S. (1989) Mol. Carcinog. 2, 159-167] to inhibit the growth of ras-transformed cells without affecting that of nontransformed cells. In oocytes, the antibiotic exerts an inhibitory action on both a ras-dependent and a ras-independent pathway. Lack of an effect of azatyrosine on germinal vesicle breakdown induced by the microinjection of an extract from mature oocytes, however, suggests that azatryosine is acting upstream of maturation-promoting factor activation.
Campa
M J
MJ
Division of Cell Biology, Burroughs Wellcome Co., Research Triangle Park, NC 27709.
Glickman
J F
JF
Yamamoto
K
K
Chang
K J
KJ
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D016203:CDC2 Protein Kinase / Q000032:analysis / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D015151:Immunoblotting; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D007700:Kinetics; D016200:Maturation-Promoting Factor / Q000494:pharmacology*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009865:Oocytes / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D010455:Peptides / Q000138:chemical synthesis / Q000276:immunology; D010750:Phosphoproteins / Q000302:isolation & purification / Q000378:metabolism*; D010766:Phosphorylation; D011374:Progesterone / Q000494:pharmacology*; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics / Q000502:physiology*; D014443:Tyrosine; D014982:Xenopus laevis
D000911:Antibodies, Monoclonal; D010455:Peptides; D010750:Phosphoproteins; D014443:Tyrosine; D011374:Progesterone; D007334:Insulin-Like Growth Factor I; D016203:CDC2 Protein Kinase; D016200:Maturation-Promoting Factor; D016283:Proto-Oncogene Proteins p21(ras)