The human synapsin II gene promoter. Possible role for the transcription factor zif268/egr-1, polyoma enhancer activator 3, and AP2.
Synapsin II is a neuron-specific phosphoprotein that selectively binds to small synaptic vesicles in the presynaptic nerve terminal. Here we report the cloning and sequencing of the 5'-flanking region of the human synapsin II gene. This sequence is very GC-rich and lacks a TATA or CAAT box. Two major transcriptional start sites were mapped. A hybrid gene consisting of the Escherichia coli chloramphenicol acetyltransferase gene under the control of 837 base pairs of the synapsin II 5'-upstream region was transfected into neuronal and nonneuronal cells. While reporter gene expression was low in neuroblastoma and non-neuronal cells, high chloramphenicol acetyltransferase activities were monitored in PC12 pheochromocytoma cells. However, there was no correlation between reporter gene expression in the transfected cells and endogenous synapsin II immunoreactivity. Using DNA-protein binding assays we showed that the transcription factors zif268/egr-1, polyoma enhancer activator 3 (PEA3), and AP2 specifically contact the synapsin II promoter DNA in vitro. Moreover, the zif268/egr-1 protein as well as PEA3 were shown to stimulate transcription of a reporter gene containing synapsin II promoter sequences. In the nervous system, zif268/egr-1 functions as a "third messenger" with a potential role in synaptic plasticity. PEA3 is expressed in the brain and its activity is regulated by proteins encoded from non-nuclear oncogenes. We postulate that zif268/egr-1 and PEA3 couple extracellular signals to long-term responses by regulating synapsin II gene expression.
Petersohn
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Institute for Genetics, University of Cologne, Germany.
Schoch
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Brinkmann
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Thiel
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D000310:Adrenal Gland Neoplasms; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000378:metabolism*; D016466:CHO Cells; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis; D003001:Cloning, Molecular; D006224:Cricetinae; D017931:DNA Primers; D015342:DNA Probes; D004268:DNA-Binding Proteins / Q000378:metabolism*; D051766:Early Growth Response Protein 1; D005786:Gene Expression Regulation; D015972:Gene Expression Regulation, Neoplastic; D005910:Glioma; D006367:HeLa Cells; D015186:Hominidae / Q000235:genetics*; D006801:Humans; D017874:Immediate-Early Proteins; D007668:Kidney; D008969:Molecular Sequence Data; D009447:Neuroblastoma; D016716:PC12 Cells; D010673:Pheochromocytoma; D011401:Promoter Regions, Genetic; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000378:metabolism; D016704:Synapsins / Q000096:biosynthesis / Q000235:genetics*; D016385:TATA Box; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D015342:DNA Probes; D004268:DNA-Binding Proteins; C497325:EGR1 protein, human; D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat; D017874:Immediate-Early Proteins; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D016704:Synapsins; D050656:Transcription Factor AP-2; D014157:Transcription Factors; C065788:transcription factor PEA3; D015500:Chloramphenicol O-Acetyltransferase