Functional properties of the unc-64 gene encoding a Caenorhabditis elegans syntaxin.
Phenotypes of Caenorhabditis elegans unc-18 and unc-64 gene mutations are similar. While unc-18 is known to be essential for normal synaptic transmission (Hosono, R., Hekimi, S., Kamiya, Y., Sassa, T., Murakami, S., Nishiwaki, S., Miwa, J., Taketo, A., and Kodaira, K.-I. (1992) J. Neurochem. 58, 1517-1525), the function of unc-64 remains unclear. Here we describe the cloning, and the molecular and genetic characterization of the unc-64 gene, especially in relation to unc-18. unc-64 encodes a protein (C. elegans syntaxin) showing sequence and structural similarities to mammalian syntaxin 1A. From unc-64, at least three types of poly(A)+ RNA are transcribed, which encode two types of syntaxin that differ in the deduced transmembrane domain. In gene expression, unc-64 closely resembles unc-18, that is, both are expressed in neural cells, especially in motor neurons and neurons constituting head ganglions. C. elegans syntaxin binds to UNC-18 with high affinity. The unc-64 (e246) mutation producing a mild phenotype causes an Ala-->Val conversion in the conserved COOH-terminal region in mammalian syntaxin 1A or Drosophila syntaxin-1A whose site is included in three types of transcripts. The binding of the mutant C. elegans syntaxin to UNC-18 is greatly reduced, indicating the mutation site contributes to the binding.
Ogawa
H
H
Department of Biology, Fujita Health University, Aichi, Japan.
Harada
S
S
Sassa
T
T
Yamamoto
H
H
Hosono
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D015801:Helminth Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008565:Membrane Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009419:Nerve Tissue Proteins / Q000235:genetics*; D010641:Phenotype; D010750:Phosphoproteins; D011485:Protein Binding; D011487:Protein Conformation; D050765:Qa-SNARE Proteins; D050827:Syntaxin 1; D014158:Transcription, Genetic; D033921:Vesicular Transport Proteins
D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D015801:Helminth Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D050765:Qa-SNARE Proteins; C494212:STX1A protein, human; D050827:Syntaxin 1; C082636:Unc-18 protein, C elegans; D033921:Vesicular Transport Proteins; C494215:unc-64 protein, C elegans