Abstract
Polycomb group (PcG) proteins control development and cell proliferation through chromatin-mediated transcriptional repression. We describe a transcription-independent function for PcG protein Posterior sex combs (PSC) in regulating the destruction of cyclin B (CYC-B). A substantial portion of PSC was found outside canonical PcG complexes, instead associated with CYC-B and the anaphase-promoting complex (APC). Cell-based experiments and reconstituted reactions established that PSC and Lemming (LMG, also called APC11) associate and ubiquitylate CYC-B cooperatively, marking it for proteosomal degradation. Thus, PSC appears to mediate both developmental gene silencing and posttranslational control of mitosis. Direct regulation of cell cycle progression might be a crucial part of the PcG system's function in development and cancer.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Anaphase-Promoting Complex-Cyclosome
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Animals
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Apc11 Subunit, Anaphase-Promoting Complex-Cyclosome
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Carrier Proteins / metabolism
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Cell Cycle Checkpoints*
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Cell Line
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Compound Eye, Arthropod / growth & development
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Compound Eye, Arthropod / metabolism
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Cyclin B / metabolism*
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DNA-Binding Proteins / chemistry
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Drosophila Proteins / chemistry
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Drosophila Proteins / genetics
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Drosophila Proteins / metabolism*
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Drosophila melanogaster / cytology
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Drosophila melanogaster / embryology
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Drosophila melanogaster / metabolism
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G2 Phase Cell Cycle Checkpoints
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Gene Silencing
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Imaginal Discs / metabolism
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Mitosis*
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Phenotype
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Polycomb Repressive Complex 1
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Proteasome Endopeptidase Complex / metabolism
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Protein Binding
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Protein Interaction Domains and Motifs
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RNA Interference
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Transcription, Genetic
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Ubiquitin-Protein Ligase Complexes / metabolism
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Ubiquitination
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Wings, Animal / growth & development
Substances
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Carrier Proteins
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CycB protein, Drosophila
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Cyclin B
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DNA-Binding Proteins
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Drosophila Proteins
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Pc protein, Drosophila
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Psc protein, Drosophila
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Ubiquitin-Protein Ligase Complexes
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Anaphase-Promoting Complex-Cyclosome
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Apc11 Subunit, Anaphase-Promoting Complex-Cyclosome
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Polycomb Repressive Complex 1
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lmgA protein, Drosophila
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Proteasome Endopeptidase Complex