Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The 5'-terminal region of the rat gene for the neuron-specific phosphoprotein, synapsin I, was isolated and sequenced. It comprises 1472 nucleotides (nt) of 5'-flanking sequence, 507 nt of the first exon, and 242 nt of the first intron. A single transcription start site was mapped by primer extension and S1 nuclease analysis. A sequence of 340 nt upstream from the transcription start site and the first exon are G+C-rich and enriched in CpG dinucleotides, resembling a CpG island. The 5'-flanking sequence lacks TATA and CAAT consensus elements but contains a consensus motif for the cAMP-responsive element. Furthermore, we notice two potential consensus motifs which are also found in corresponding positions in the genes for the nerve growth factor receptor and the 68-kDa neurofilament protein. The 5'-terminal region of the human synapsin I gene was also cloned and sequenced. A high degree of sequence conservation between rat and human is found in the upstream 340 nt that coincides precisely with the G+C-rich domain and includes the consensus elements, and throughout the first exon including the untranslated sequence. Sequence conservation is also observed further upstream and at the beginning of the first intron. In a transient chloramphenicol acetyltransferase expression assay, 5'-flanking sequences of the rat synapsin I gene function as strong promoters in neuroblastoma cells, but not in fibroblastoid cells. 225 nt of 5'-flanking sequence and 105 nt of 5'-untranslated sequence are sufficient for cell-type specific transcription in this assay.
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PMID:The 5'-flanking region of the synapsin I gene. A G+C-rich, TATA- and CAAT-less, phylogenetically conserved sequence with cell type-specific promoter function. 211 19

Synapsin II is an abundant peripheral membrane protein of synaptic vesicles that is expressed exclusively in neuronal cells. Here we report the isolation and characterization of the 5'-terminal region of the murine synapsin II gene. Primer extension and S1 nuclease protection analysis show that synapsin II gene transcription is initiated from a unique site. The synapsin II gene promoter contains no canonical TATA or CAAT boxes but has putative binding sites for the transcription factors Sp1, AP2, and NGFIA. This promoter is embedded in a large G+C-rich domain with characteristics of a CpG island. Transfection experiments using synapsin II-luciferase fusion genes demonstrate that the 5'-flanking sequence functions as a strong promoter in neuronal but not in nonneuronal cells. Deletion analysis reveals the presence of a neuron-specific core promoter (-79 to 153) and, upstream, two positive and one negative regulatory elements. The 5'-terminal region of the murine synapsin I gene was also cloned and sequenced. Although there is no extensive sequence homology between the 5'-flanking regions of the synapsin I and II genes, comparison analysis has identified two regions of homologous sequences, which may be involved in determining neuron specificity of the core promoters of these two genes.
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PMID:Neuron-specific expression of the synapsin II gene is directed by a specific core promoter and upstream regulatory elements. 803 99