Wan D C, Choi R C, Siow N L, Tsim K W
Department of Biochemistry, The Chinese University of Hong Kong, Shatin, China.
Neurosci Lett. 2000 Jul 7;288(1):81-5. doi: 10.1016/s0304-3940(00)01200-3.
Different transcription elements have been proposed to play a role in the regulation of acetylcholinesterase (AChE) in muscle and neuron, and cyclic adenosine 3',5'-monophosphate (cAMP)-dependent pathway is one of them. In order to test the possible role of cAMP in regulating the expression of human AChE, an approximately 2.2 kb DNA fragment of human AChE promoter was linked up stream to a luciferase reporter. The chimeric DNA was transfected into cultured NG108-15 neuroblastoma cells. Application of Bt(2)-cAMP and forskolin increased the promoter driven luciferase activity over 2-fold in the transfected NG108-15 cells; the increase was parallel to the activation of endogenous AChE protein and enzymatic activity. The intracellular cAMP level was increased in the Galpha(sQL) (constitutively active mutant of Galpha(s)) cDNA transfected NG108-15 cells. The Galpha(sQL) cDNA transfected cells showed an increase of over 10-fold in the luciferase activity. In addition, a constitutively active mutant of activating transcription factor-1 (ATF-1) was able to turn on human AChE promoter by approximately 4-fold when they were co-expressed in the neuroblastoma cells. These results support the involvement of a cAMP-dependent pathway in regulating the expression of human AChE.
不同的转录元件被认为在肌肉和神经元中乙酰胆碱酯酶(AChE)的调节中发挥作用,环磷酸腺苷(cAMP)依赖性途径就是其中之一。为了测试cAMP在调节人AChE表达中的可能作用,将一段约2.2 kb的人AChE启动子DNA片段连接到荧光素酶报告基因的上游。将嵌合DNA转染到培养的NG108-15神经母细胞瘤细胞中。在转染的NG108-15细胞中,应用Bt(2)-cAMP和福斯可林可使启动子驱动的荧光素酶活性增加2倍以上;这种增加与内源性AChE蛋白的激活和酶活性平行。在转染了Gα(sQL)(Gα(s)的组成型活性突变体)cDNA的NG108-15细胞中,细胞内cAMP水平升高。转染了Gα(sQL) cDNA的细胞的荧光素酶活性增加了10倍以上。此外,当组成型活性的激活转录因子-1(ATF-1)突变体在神经母细胞瘤细胞中共同表达时,能够使人类AChE启动子开启约4倍。这些结果支持cAMP依赖性途径参与调节人AChE的表达。