Identification of the promoter region and the 5'-untranslated exons of the human voltage-gated sodium channel Nav1.1 gene (SCN1A) and enhancement of gene expression by the 5'-untranslated exons.
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.
Long
Yue-Sheng
YS
Institute of Neuroscience and the Second Affiliated Hospital, Guangzhou Medical College, Guangdong, China.
Zhao
Qi-Hua
QH
Su
Tao
T
Cai
Yang-Lin
YL
Zeng
Yang
Y
Shi
Yi-Wu
YW
Yi
Yong-Hong
YH
Chang
Hao-Hui
HH
Liao
Wei-Ping
WP
D020121:5' Untranslated Regions / Q000235:genetics*; D001483:Base Sequence; D001921:Brain / Q000502:physiology; D002460:Cell Line; D005091:Exons / Q000235:genetics*; D015870:Gene Expression; D005786:Gene Expression Regulation; D006801:Humans; D008969:Molecular Sequence Data; D062550:NAV1.1 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D015222:Sodium Channels / Q000235:genetics*
D020121:5' Untranslated Regions; D062550:NAV1.1 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins; C568242:SCN1A protein, human; D015222:Sodium Channels