HGNC Approved Gene Symbol: SYN3Cytogenetic location: 22q12.3 Genomic coordinates (GRCh38): 22:32,507,819-33,058,380 (from NCBI)▼ Cloning and ExpressionSynaps...
HGNC Approved Gene Symbol: SYN3
Cytogenetic location: 22q12.3 Genomic coordinates (GRCh38): 22:32,507,819-33,058,380 (from NCBI)
▼ Cloning and Expression
Synapsins are a family of neuron-specific synaptic vesicle-associated phosphoproteins that have been implicated in synaptogenesis and in the modulation of neurotransmitter release. In mammals, distinct genes for synapsins I (SYN1; 313440) and II (SYN2; 600755) have been identified, each of which encodes 2 alternatively spliced isoforms. Kao et al. (1998) cloned and characterized a third member of the synapsin gene family, synapsin III, from human DNA. Synapsin III gives rise to at least 1 protein isoform, designated synapsin IIIa, in several mammalian species. Synapsin IIIa is associated with synaptic vesicles, and its expression appears to be neuron-specific. The primary structure of synapsin IIIa conforms to the domain model previously described for the synapsin family, with domains A, C, and E exhibiting the highest degree of conservation. Synapsin IIIa contains a novel domain, termed domain J, located between domains C and E. The similarities among synapsins I, II, and III in domain organization, neuron-specific expression, and subcellular localization suggested a possible role for synapsin III in the regulation of neurotransmitter release and synaptogenesis.
Hosaka and Sudhof (1998) identified the human SYN3 gene. Among the rat tissues tested, they found that Syn3 was expressed only in brain. As in other synapsins, the C domain of Syn3 bound ATP with high affinity and ADP with a lower affinity, consistent with a cycle of ATP binding and hydrolysis. However, unlike with Syn1 and Syn2, calcium inhibited ATP binding to Syn3. The authors concluded that calcium has distinct regulatory effects on Syn1, Syn2, and Syn3.
Kao et al. (1998) found that an anonymous marker from 22q12-q13, D22S280, was located within an intron between exons 2 and 4 of the SYN3 gene.
▼ Gene Function
Kao et al. (1998) noted that the 22q12-q13 region had previously been identified as a potential schizophrenia susceptibility locus (600850). D22S278, which was shown by the Schizophrenia Collaborative Linkage Group (Chromosome 22) (1996) to be significantly associated with schizophrenia, was approximately 4.5 cM removed from D22S280, located within an intron of the SYN3 gene.
From a study in Taiwan, Tsai et al. (2002) presented data that did not support a large effect of the synapsin III gene in the pathogenesis of schizophrenia. They performed systematic sequencing of the protein coding and 5-prime promoter regions in 62 Han Chinese schizophrenic patients with a positive family history. Further case-control association studies were performed using genetic polymorphic markers.