背景资料:Kaposi's sarcoma-associated herpesvirus (KSHV) belongs to the gamma-(2)-herpesvirus subfamily and has been closely linked to the Kaposi’s sarcoma, primary effusion lymphoma (PEL) and multicentric Castleman’s disease. The genome of KSHV is 165-170 kb and contains at least 88 open reading frames. ORF45 protein encoded by an immediate-early gene in the KSHV genome is characterized as a phosphorylated protein, and it is localized in the cytoplasm of infected cells. Studies have shown that ORF45 Protein interacted with cellular IRF-7 and blocked virus-mediated phosphorylation and nuclear translocation of IRF-7. In consequence, ORF45 efficiently inhibited virus-induced production of type I IFN. Zhu et al (2003) reported that the ORF45 Protein was associated with purified virions.