CREB-binding protein transcription activation domain for enhanced transgene expression by a positive feedback system

Abstract

The positive feedback system using a fusion protein of the sequence-specific DNA binding domain of yeast GAL4 and the transcription activation domain of herpes simplex virus VP16 (GAL4-VP16), in which GAL4-VP16 promotes its own expression as well as that of a reporter gene product, is useful for efficient transgene expression from plasmid DNA. In this study, the transcription activation domains of endogenous proteins, instead of VP16, were fused to the GAL4 DNA binding domain, and the positive feedback systems employing the novel fusion proteins were examined. Plasmid DNAs encoding the transcription factors were introduced into mouse Hepa 1-6 cells by electroporation and lipofection. Among CREB-binding protein (226-460), sterol regulatory element-binding protein-1 (1-140), p53 (1-70), and Med15 (9-73), the CREB-binding protein functioned efficiently as an activator. These results indicated that the GAL4-CREB-binding protein is useful for enhanced transgene expression by the positive feedback system.