RT Journal Article
SR Electronic
T1 Structural and Functional Characterization of the Human α3 Nicotinic Subunit Gene Promoter
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 250
OP 261
DO 10.1124/mol.51.2.250
VO 51
IS 2
A1 Diego Fornasari
A1 Elena Battaglioli
A1 Adriano Flora
A1 Susanna Terzano
A1 Francesco Clementi
YR 1997
UL http://molpharm.aspetjournals.org/content/51/2/250.abstract
AB We describe the structural and functional features of the human α3 nicotinic receptor subunit promoter. A 0.35-kb region immediately upstream of the start codon was identified that when transfected in human neuroblastoma cells was able to drive the expression of the luciferase reporter gene with a strength comparable to that of the well-characterized simian virus 40 promoter/enhancer. This region displayed the features of a multistart-site, GC-rich, TATA-less, and CAAT-less promoter, containing many overlapping Sp1 and AP-2 putative binding sites. Further dissections of the 0.35-kb fragment revealed that its 3′ region, specifying the 5′ UT of the mRNA, plays a relevant positive effect in determining the strength of the promoter. This region contains putative cis-acting elements for AP-2, nuclear factor-κB, and the recently described multiple-start site element downstream-1. By mutation analysis, we showed that these sites are functional and when combined increase the promoter activity by 4-fold. The 0.35-kb promoter was found to be under the negative control of upstream sequences that include a modern Alu repeat. The α3 Alu repeat works as a composite region, containing both positive and negative elements that control the activity of the downstream promoter. Finally, we investigated the tissue-specific activity of the human α3 gene 5′ regulatory sequences, showing that they are able to drive the expression of the reporter gene preferentially in neuronal cells.