Molecular mechanism and prevention of drug dependence

点击翻译按钮获取中文摘要

Chronic administration of morphine to NG108-15 cells or mice decreased the binding activity of a nuclear factor (ssCRE-BP) tosingle-stranded oligo-DNA of cAMP-response element (ssCRE). we have purified ssCRE-BP from mouse cerebella and isolated the cDNA clone. We found that ssCRE-BP from mouse brain was identical to Pura, which is a binding protein for single-stranded purine-rich DNA sequences that was originally isolated as a replication factor. ssCRE-BP was abundant in the cerebral cortex and cerebellum, but very low levels were detected in other tissues. Examination of the effect of chronic morphine treatment on the amount of ssCRE-BP in mouse brain showed that ssCRE-BP was not influenced by chronic morphine treatment significantly in western blot analysis. Although the DNA binding activities of purified ssCRE-BP or its GST-fusion protein were very low, they were markedly enhanced by the addition of an activator that was about 100kDa, trypsin sensitive and heat stable. The activator can be substituted with casein, which increased the affinity of ssCRE-BP for DNA by one order. A series of deletion mutants were prepared for determining the DNA binding-and activator-interacting domains and both of them were found to reside in AA 50-215 of ssCRE-BP.Although ssCRE-BP was abundant in the brain, the activator was ubiquitous. Characterization of the activator may provide insight into the physiological roles of ssCRE-BP which is involved in the development of morphine dependence and tolerance.