Induction of reinitiation of meiosis in amphibian Bufo and Xenopus oocytes by injection of M-phase extracts of ciliate Tetrahymena needs the recipient protein synthesis.
We show here that germinal vesicle breakdown of amphibian Bufo and Xenopus oocytes can be induced if ciliate Tetrahymena extracts are injected into them. The activity of meiosis-reinitiation-inducing factor (MRIF) appeared only a M-phase of a synchronously dividing culture, indicating that this MRIF has an important function for induction of M-phase in the mitotic cell cycle. MRIF of Tetrahymena differed from MPF (M-phase-promoting factor), because its action on the induction of GVBD was inhibited by cycloheximide and it could not induce GVBD in starfish oocytes by microinjection. MPF activity was not detected in extracts of vegetatively growing Tetrahymena. Preliminary experiments showed that MRIF was a heat-labile, Ca2(+)-sensitive, and trypsin-sensitive soluble protein.
Fujishima
M
M
Biological Institute, Faculty of Science, Yamaguchi University, Japan.
Kodama
I
I
Hori
M
M
Hori
M
M
Katsu
Y
Y
Imai
R
R
D000818:Animals; D002023:Bufo bufo; D002118:Calcium / Q000502:physiology; D002457:Cell Extracts; D003513:Cycloheximide / Q000494:pharmacology; D016200:Maturation-Promoting Factor / Q000502:physiology*; D008540:Meiosis / Q000502:physiology*; D008938:Mitosis; D009865:Oocytes / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects; D013215:Starfish; D013768:Tetrahymena / Q000502:physiology*; D014357:Trypsin; D014982:Xenopus laevis
D002457:Cell Extracts; D003513:Cycloheximide; D016200:Maturation-Promoting Factor; D014357:Trypsin; D002118:Calcium