摘要
目的 探讨脆性X智力低下一号基因 (FMR1)表达缺失对环磷酸腺苷 (cAMP)的影响及其机制。方法 通过硝普钠封闭FMR1,建立脆性X综合征细胞模型 ;研究FMR1表达缺失对cAMP水平及cAMP代谢途径中的两个关键酶 [腺苷酸环化酶 (AC)及磷酸二酯酶 (PDE) ]活性的影响。结果 在细胞水平 ,硝普钠可成功地封闭FMR1基因 ;基因封闭组细胞内cAMP水平明显低于对照组 (P =0 0 0 0 ) ;该组腺苷酸环化酶的比活力明显低于对照组 (P =0 0 0 0 ) ,而磷酸二酯酶比活力则无显著改变(P =0 983)。结论 FMR1基因表达缺失可导致细胞内cAMP的水平降低 ,腺苷酸环化酶活性被抑制可能是其降低的原因之一。
Objective To study the influence of defection of Fragile X mental retardation-1 gene (FMR1) on cyclic adenosine monophosphate (cAMP) and to discuss its mechanism. Methods FMR1 gene of peripheral blood mononuclear cell was silenced in vitro by sodium nitrointroprusside. The effect of gene-silencing was detected using reverse transcript polymerase chain reaction (RT-PCR). The specific activity of adenylate cyclase and phosphodiesterase was showed by the activity ratio of yield or consumption of cAMP during a unit time. Spectrophotometry was used to measure the two key enzymes (adenylate cyclase and phosphodiesterase), as to determining the level of intracellular cyclic adenosine monophosphate in the process of cAMP metabolism. Results FMR1 gene was fully silenced by sodium nitrointroprusside at 12th, 24th and 48th hour separately, re-expressed at 72th hour. If the cultivated fluild was replaced with new sodium nitrointroprusside at 48th hour, FMR1 gene would be silenced continuously. The intracellular cAMP level in the gene silenced group was lower, and significant depression of adenylate cyclase specific activity was found in the FMR1 gene silenced group (P=0.000). No significant difference was found on phosphodiesterase specific activity (P=0.983). Conclusions The results suggest that the yield of cAMP could be influenced by defection of FMR1. The depression of adenylate cyclase activity might be one of the causes of the decrease of intracellular cAMP production.
出处
《中华神经科杂志》
CAS
CSCD
北大核心
2004年第2期162-165,共4页
Chinese Journal of Neurology
