Abstract
In order to characterize the mechanisms regulating neuronal expression of the nematode SNAP-25 gene, we identified the SNAP-25 genes of Caenorhabditis elegans and Caenorhabditis briggsae. Comparative sequence analysis and reporter assays revealed two putative 5' regulatory elements, P1 and P2, and four elements, I1h, I1m, I2h, and I2m, in the first intron. Nuclear extracts contained activities that bound the P2 and I1h elements. Different elements were required for SNAP-25 expression in different neuronal subsets; P1 was required in DA and DD motor neurons, and I1m and I2m were required in DB and DA neurons, respectively. P2 was active in amphid and phasmid neurons, I1h in pharyngeal neurons, and I2h in touch receptor neurons. The I2h element contained a putative binding site for transcription factor UNC-86. Both UNC-86 and MEC-3 were required for I2h activity in the mechanosensory neurons: in these neurons, GFP expression driven by I2h was abolished in animals bearing either an unc-86 null or a mec-3 null mutation, or an unc-86 mutation that leads to defective interaction with MEC-3. Deletion of the MEC-3 binding site also abolished the GFP expression. Gel mobility-shift assay results suggest that transcriptional regulation of SNAP-25 may involve multiple transcription factors.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Base Sequence
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Caenorhabditis elegans / genetics*
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Caenorhabditis elegans / metabolism
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Caenorhabditis elegans Proteins / genetics*
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Caenorhabditis elegans Proteins / metabolism
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Cells, Cultured
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Cloning, Molecular
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Electrophoretic Mobility Shift Assay
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Gene Expression Regulation
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Green Fluorescent Proteins
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Homeodomain Proteins / genetics
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Homeodomain Proteins / metabolism
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LIM-Homeodomain Proteins
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Luminescent Proteins
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Membrane Proteins / genetics*
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Membrane Proteins / metabolism
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Molecular Sequence Data
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Mutagenesis, Site-Directed
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Nerve Tissue Proteins / genetics*
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Nerve Tissue Proteins / metabolism
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Neurons, Afferent / cytology
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Neurons, Afferent / metabolism*
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POU Domain Factors
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Promoter Regions, Genetic / genetics*
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RNA, Messenger / analysis
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Regulatory Sequences, Nucleic Acid*
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Sequence Deletion
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Sequence Homology, Amino Acid
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Sequence Homology, Nucleic Acid
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Synaptosomal-Associated Protein 25
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Transcription Factors / genetics
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Transcription Factors / metabolism
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Transcription, Genetic*
Substances
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Caenorhabditis elegans Proteins
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Homeodomain Proteins
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LIM-Homeodomain Proteins
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Luminescent Proteins
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Membrane Proteins
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Nerve Tissue Proteins
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POU Domain Factors
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RNA, Messenger
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Synaptosomal-Associated Protein 25
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Transcription Factors
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mec-3 protein, C elegans
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unc-86 protein, C elegans
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Green Fluorescent Proteins