A TRANSCRIPTIONAL REGULATORY ELEMENT CRITICAL FOR CHRNB4 PROMOTER ACTIVITY IN VIVO

作者：Scofield M D; Tapper A R; Gardner P D^*

来源：Neuroscience, 2010, 170(4): 1056-1064.

DOI：10.1016/j.neuroscience.2010.08.007

• nicotinic acetylcholine receptors
• CHRNB4
• Sp1
• CACCC
• transgenic mice

Genome-wide association studies have underscored the importance of the clustered neuronal nicotinic acetylcholine receptor (nAChR) subunit genes with respect to nicotine dependence as well as lung cancer susceptibility. CHRNB4, which encodes the nAChR beta 4 subunit, plays a major role in the molecular mechanisms that govern nicotine withdrawal. Thus, elucidating how expression of the beta 4 gene is regulated is critical for understanding the pathophysiology of nicotine addiction. We previously identified a CA box regulatory element, (5'-CCACCCCT-3') critical for beta 4 promoter activity in vitro. We further demonstrated that a 2.3-kb fragment of the beta 4 promoter region containing the 5'-CCACCCCT-3' regulatory element in the beta 4 gene promoter (CA box) is capable of directing cell-type specific expression of a reporter gene to a myriad of brain regions that endogenously express the beta 4 gene. To test the hypothesis that the CA box is critical for beta 4 promoter activity in vivo, transgenic animals expressing a mutant form of the beta 4 promoter were generated. Reporter gene expression was not detected in any tissue or cell type at embryonic day 18.5 (ED 18.5). Similarly, we observed drastically reduced reporter gene expression at postnatal day 30 (PD30) when compared to wild type (WT) transgenic animals. Finally, we demonstrated that CA box mutation results in decreased interaction of the transcription factor Sp1 with the mutant beta 4 promoter. Taken together these results demonstrate that the CA box is critical for beta 4 promoter activity in vivo.

• 出版日期2010-11-10