Identification of the promoter region and the 5'-untranslated exons of the human voltage-gated sodium channel Na(v)1.1 gene (SCN1A) and enhancement of gene expression by the 5'-untranslated exons.
J Neurosci Res. 2008 Jul 24;
Authors: Long YS, Zhao QH, Su T, Cai YL, Zeng Y, Shi YW, Yi YH, Chang HH, Liao WP
Voltage-gated sodium channels play critical roles in the excitability of the brain. A decreased level of Na(v)1.1 has been identified as the cause of severe myoclonic epilepsy in infancy. In the present study, we identified the transcription start site and three 5'-untranslated exons of SCN1A by using 5'-full RACE. The 2.5-kb region upstream of the transcription start site was targeted as a potential location of the promoter. The 2.5-kb genomic fragment (P(2.5), from +26 to -2,500) and the 2.7-kb fragment (P(2.7), P(2.5) combined with the 227-bp 5'-untranslated exons) were cloned to produce luciferase constructs. The P(2.5) and the P(2.7) drove luciferase gene expression in the human neuroblastoma cell line SH-SY5Y but not in the human embryonic kidney cell line HEK-293. The 5'-untranslated exons could greatly enhance gene expression in SH-SY5Y cells. The P(2.7) could be used as a functional unit to study the role of SCN1A noncoding sequences in gene expression. These findings will also help in exploring the possibility of promoter mutant-induced diseases and revealing the mechanism underlying the regulation of SCN1A expression in the normal brain. (c) 2008 Wiley-Liss, Inc.
PMID: 18655196 [PubMed - as supplied by publisher]
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