Two distinct regulatory elements control quail cdc2 transcription: possible involvement in the control of retinoblast differentiation.
It is a characteristic of the central nervous system of higher eukaryotes that neurons, after an initial proliferation phase, remain postmitotic for their whole life span. In the developing quail neuroretina, most retinoblasts become postmitotic after 7-8 days of incubation. They also cease to express cdc2, which is presumably necessary to allow retinoblasts to definitively leave the cell cycle. The molecular mechanisms monitoring cdc2 expression during differentiation remain partly understood. To further study the control of cdc2 transcription in avian cells, we have cloned the quail cdc2 promoter. Two functional regulatory elements have been characterized. One of them contains an E2F-binding site. Human E2F-1 was found to transactivate the quail cdc2 promoter very efficiently in avian and human cells. Gel retardation experiments are presented, suggesting that E2F, in association with different partners, is a major regulatory of cdc2 transcription during the development of the neuroretina. Our data also indicate that another transcription factor binds to the octamer CAGGTGGC located 115 nucleotides above the main transcription start site. This motif is thus another important regulatory element participating in the control of cdc2 expression.
North
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UMR 49 CNRS, Ecole normale supérieure de Lyon, France.
Espanel
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Tavitian
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Brun
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Gillet
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G
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D016203:CDC2 Protein Kinase / Q000235:genetics*; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002454:Cell Differentiation; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins; D015536:Down-Regulation; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D006801:Humans; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics; D011784:Quail; D012333:RNA, Messenger / Q000096:biosynthesis; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics*; D012160:Retina / Q000166:cytology* / Q000196:embryology / Q000254:growth & development; D016160:Retinoblastoma Protein / Q000096:biosynthesis; D056465:Retinoblastoma-Binding Protein 1; D016415:Sequence Alignment; D050680:Transcription Factor DP1; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics*; D015533:Transcriptional Activation
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; D012333:RNA, Messenger; D016160:Retinoblastoma Protein; D056465:Retinoblastoma-Binding Protein 1; D050680:Transcription Factor DP1; D014157:Transcription Factors; D004247:DNA; D016203:CDC2 Protein Kinase