Differential effects of 6-DMAP, olomoucine and roscovitine on Xenopus oocytes and eggs.
The effects of the new cyclin-dependent kinase inhibitors, roscovitine and olomoucine, on oocytes and eggs of Xenopus laevis were investigated and compared with those of 6-dimethylamino purine (6-DMAP). The inhibitory properties of 6-DMAP, olomoucine and roscovitine towards p34cdc2-cyclin B isolated from Xenopus eggs revealed K-IC50 values of 300, 40 and 10 microM respectively. The three compounds inhibited progesterone-induced maturation with M-IC50 values of 200, 100 and 20 microM. These values were consistent with the K-IC50 values but the ratio M-IC50/K-IC50 was higher for roscovitine and olomoucine than for 6-DMAP. The disappearance of spindle and condensed chromosomes without pronucleus formation was observed when 1 mM 6-DMAP was applied for 4 h at germinal vesicle breakdown or at metaphase II, whereas no effect was observed using 1 mM olomoucine or 50 microM roscovitine. Changes in the electrophoretic mobility of p34cdc2 and erk2 were observed only in homogenates of matured oocytes or eggs exposed for 4 h to 1 mM 6-DMAP. When the drugs were microinjected into matured oocytes, olomoucine (100 microM) and roscovitine (50 microM) induced pronucleus formation more efficiently than did 6-DMAP (100 microM). Taken together, these results demonstrate that Xenopus oocytes possess a lower permeability to olomoucine and roscovitine and that these new compounds are suitable for in vivo studies after germinal vesicle breakdown provided they are microinjected.
Flament
S
S
Centre de Biologie Cellulaire, UPRES EA 1033, Université de Lille, Villeneuve d'Ascq, France.
Bodart
J F
JF
Bertout
M
M
Browaeys
E
E
Rousseau
A
A
Vilain
J P
JP
D000225:Adenine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D016203:CDC2 Protein Kinase / Q000378:metabolism; D019926:Cyclin B / Q000378:metabolism; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D007701:Kinetin; D008540:Meiosis / Q000187:drug effects; D008845:Microinjections; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D009865:Oocytes / Q000166:cytology* / Q000187:drug effects; D010063:Ovum / Q000166:cytology* / Q000187:drug effects; D011494:Protein Kinases / Q000378:metabolism; D011687:Purines / Q000494:pharmacology*; D000077546:Roscovitine; D014982:Xenopus laevis
D019926:Cyclin B; D004791:Enzyme Inhibitors; D011687:Purines; D000077546:Roscovitine; C001020:N(6),N(6)-dimethyladenine; C090046:olomoucine; D011494:Protein Kinases; C102333:histone H1 kinase; D016203:CDC2 Protein Kinase; D018844:Cyclin-Dependent Kinases; D019950:Mitogen-Activated Protein Kinase 1; D000225:Adenine; D007701:Kinetin