The human cytomegalovirus (HCMV) IE86 cDNA was cloned into pGEX-2T and fusion protein GST-IE86 was expressed in E. coli. SDS-PAGE and Western blot assay indicated that fusion protein GST-IE86 with molecular weight of 92 ku is soluble in the supernatant of cell lysate. Protein GST and fusion protein GST-IE86 were purified by affinity chromatography. The technology of co-separation and specific affinity chromatography was used to study the interactions of HCMV IE86 protein with some transcriptional regulatory proteins and transcriptional factors. The results indicated that IE86 interacts separately with transcriptional factor TFIIB and promoter DNA binding transcription frans-activating factors SP1, AP1 and AP2 to form a heterogenous protein complex. These transcriptional frans-activating factors, transcriptional factor and IE86 protein were adsorbed and retained in the affinity chromatography simultaneously. But IE86 protein could not interact with NF-κB, suggesting that the function of IE86 protein that can interact with transcriptional factor and transcriptional frans-activating factors has no relevance to protein glycosylation. IE86 protein probably has two domains responsible for binding transcriptional frans-activating regulatory proteins and transcriptional factors respectively, thus activating the transcription of many genes. The interactions accelerated the assembly of the transcriptional initiation complexes.
