Bruno inhibits the expression of mitotic cyclins during the prophase I meiotic arrest of Drosophila oocytes.
Animal oocytes undergo a highly conserved developmental arrest in prophase of meiosis I. The maintenance of the prophase I arrest requires the silencing of Cdk1 activity. Drosophila oocytes inhibit the accumulation of the mitotic cyclins, the activating subunits of Cdk1, via a poorly defined posttranscriptional mechanism. Here, we demonstrate that the translational repressor Bruno binds the 3' UTR and inhibits the translation of the mitotic cyclin Cyclin A during prophase of meiosis I. In the absence of Bruno, ovarian cysts enter meiosis but rapidly accumulate high levels of mitotic cyclins and return to the mitotic cycle. Based on our results, we propose a model in which Bruno and the anaphase-promoting complex/cyclosome act together to restrict the accumulation of the mitotic cyclins, and thus Cdk1 activity, during the prophase I arrest of the Drosophila oocyte.
Sugimura
Isamu
I
Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
Lilly
Mary A
MA
D020413:3' Untranslated Regions / Q000502:physiology; D000818:Animals; D030801:Animals, Genetically Modified; D015152:Blotting, Northern / Q000379:methods; D015153:Blotting, Western / Q000379:methods; D016203:CDC2 Protein Kinase / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism; D019925:Cyclin A / Q000378:metabolism; D019926:Cyclin B / Q000378:metabolism; D016213:Cyclins / Q000145:classification / Q000378:metabolism*; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D047468:Immunoprecipitation / Q000379:methods; D007211:Indoles; D049469:Meiotic Prophase I / Q000502:physiology*; D009865:Oocytes / Q000502:physiology*; D010053:Ovary / Q000502:physiology; D011485:Protein Binding / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis; D016601:RNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014404:Tubulin / Q000378:metabolism
D020413:3' Untranslated Regions; D018797:Cell Cycle Proteins; D019925:Cyclin A; D019926:Cyclin B; D016213:Cyclins; D029721:Drosophila Proteins; D007211:Indoles; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D014404:Tubulin; C093437:bru1 protein, Drosophila; D049452:Green Fluorescent Proteins; C007293:DAPI; D016203:CDC2 Protein Kinase