胆汁酸
胆固醇7α羟化酶
分子生物学
心理压抑
报告基因
CYP8B1
生物化学
响应元素
电泳迁移率测定
荧光素酶
转染
生物
牛磺酸
基因
化学
氨基酸
发起人
基因表达
作者
Diane Stroup,M. Crestani,John Y.L. Chiang
出处
期刊:American Journal of Physiology-gastrointestinal and Liver Physiology
[American Physiological Society]
日期:1997-08-01
卷期号:273 (2): G508-G517
被引量:83
标识
DOI:10.1152/ajpgi.1997.273.2.g508
摘要
The transcriptional activity of the cholesterol 7 alpha-hydroxylase gene CYP7A is repressed by bile acids. Taurine conjugates of chenodeoxycholate and deoxycholate, but not cholate and ursodeoxycholate, inhibited the CYP7A promoter/luciferase reporter activity in transient transfection assays in Hep G2 cells. A region from nucleotide (nt) -74 to -55 was found to mediate bile acid response. However, deletion of this bile acid response element (BARE-I) enhanced reporter activity but did not eliminate the bile acid response. This is due to the presence of another BARE-II located in a conserved region between nt -149 and -128. Deletion or mutations of these sequences reduced promoter activity and abolished bile acid repression. This BARE-II shares an identical AGTTCAAG core sequence with BARE-I. Electrophoretic mobility shift assays of BARE-I and BARE-II probes using Hep G2 nuclear extract and the partially purified binding activity of nt -65/-54 DNA-affinity column revealed that the same or a similar nuclear protein might bind to both BAREs. BARE-II is the major BARE involved in the transcriptional repression of the CYP7A gene by hydrophobic bile acids.
科研通智能强力驱动
Strongly Powered by AbleSci AI