Translation of cyclin mRNA is necessary for extracts of activated xenopus eggs to enter mitosis.
The cyclins are a family of proteins encoded by maternal mRNA. Cyclin polypeptides accumulate during interphase and are destroyed during mitosis at about the time of entry into anaphase. We show here that Xenopus oocytes contain mRNAs encoding two cyclins that are major translation products in a cell-free extract from activated eggs. Cutting these mRNAs with antisense oligonucleotides and endogenous RNAase H blocks entry into mitosis in a cell-free egg extract. The extracts can enter mitosis if either of the cyclin mRNAs is left intact. We conclude that the synthesis of these cyclins is necessary for mitotic cell cycles in cleaving Xenopus embryos.
Minshull
J
J
Department of Biochemistry, University of Cambridge, England.
Blow
J J
JJ
Hunt
T
T
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001755:Blastocyst / Q000032:analysis; D002453:Cell Cycle / Q000187:drug effects; D004247:DNA / Q000032:analysis / Q000096:biosynthesis / Q000302:isolation & purification; D005260:Female; D008938:Mitosis / Q000187:drug effects; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000032:analysis / Q000235:genetics* / Q000494:pharmacology; D009865:Oocytes / Q000166:cytology*; D009866:Oogenesis / Q000187:drug effects; D018809:Proliferating Cell Nuclear Antigen; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics*; D014981:Xenopus
D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; D004247:DNA