Changes in patterns of protein synthesis in axolotl oocytes during progesterone-induced maturation.

SUMMARYPatterns of protein phosphorylation and synthesis during axolotl (Ambystoma mexicanum)oocyte maturation were studied by incorporatio 32 P]orthophosphatn of [ e an 35 S]methionind [ einto polypeptides, followed by two-dimensional gel electrophoresis. Various alterations wereobserved after progesterone treatment: de novo appearanc 35 S]methionine-labellee of [ d poly-peptides, a quantitative increase in previously synthesized proteins and a quantitative decreasein or disappearance of other previously synthesized proteins. Change 32 P- and 35s i S-labellinn gwere observed very early during maturation. Neither prior oocyte enucleation nor or-amanitintreatment had a significant effect on these changes. Stimulation with MPF provided the samefinal protein pattern as PG treatment. However, cholera toxin inhibited all the changes seenduring maturation. Comparisons between the pattern 35sS]methionine of [ - and32 [ P]phosphate-labelling provide further information on the biochemical events that take place during oocytematuration.INTRODUCTION