Identification of binding sites for the 86-kilodalton IE2 protein of human cytomegalovirus within an IE2-responsive viral early promoter.

摘要: The 86-kDa IE2 protein (IE86) of human cytomegalovirus (HCMV) can act as both an activator and a repressor gene expression. mechanisms for these functions are not well defined. It has recently been demonstrated that this sequence-specific DNA binding properties: it interacts directly with target sequence is located between the TATA box cap site its own promoter. This sequence, termed CRS (cis repression signal) element, required negative autoregulation IE1/IE2 enhancer/promoter by IE2. We demonstrate now to confined but occurs also within early promoter HCMV previously shown be strongly responsive. By DNase I protection analysis using purified, procaryotically expressed protein, we could identify three sites region -290 -120 UL112 HCMV. Competition in experiments gel retardation showed identified specific have high affinity. Deletion from reduced level transactivation; however, remaining still stimulated about 40-fold. Constructs which were fused did reveal significant contribution sequences transactivation. However, if was reinserted upstream nucleotide -117 promoter, increase transactivation obvious, whereas mutated mediate effect. finding suggests DNA-bound contribute seems require presence additional transcription factors. Moreover, comparison detected detect strong homology, suggesting may able interact broad spectrum different sequences.