IL-10 promoter transactivation by the viral K-RTA protein involves the host-cell transcription factors, specificity proteins 1 and 3

• Published in: The Journal of biological chemistry 2018-01, Vol.293 (2), p.662-676
• Main Authors: Miyazawa, Masanori, Noguchi, Kohji, Kujirai, Mana, Katayama, Kazuhiro, Yamagoe, Satoshi, Sugimoto, Yoshikazu
• Format: Article
• Language: English
• Subjects: Binding Sites - genetics; Binding Sites - physiology; Gene Expression Regulation, Viral - genetics; Gene Expression Regulation, Viral - physiology; herpesvirus; Humans; IL-10; interleukin; Interleukin-10 - genetics; Interleukin-10 - metabolism; Molecular Bases of Disease; Promoter Regions, Genetic - genetics; Sp1 Transcription Factor - genetics; Sp1 Transcription Factor - metabolism; SP3; Sp3 Transcription Factor - genetics; Sp3 Transcription Factor - metabolism; specificity protein 1 (Sp1); transactivation; transcription; Transcription Factors - genetics; Transcription Factors - metabolism; Transcriptional Activation - genetics; Transcriptional Activation - physiology; Viral Proteins - genetics; Viral Proteins - metabolism; viral transcription; Virus Replication - genetics; Virus Replication - physiology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M117.802900

Kaposi’s sarcoma-associated herpesvirus (KSHV)/human herpesvirus-8 (HHV-8) causes a persistent infection, presenting latent and lytic replication phases during its life cycle. KSHV-related diseases are associated with deregulated expression of inflammatory cytokines, including IL-6 and IL-10, but the mechanisms underlying this dysregulation are unclear. Herein, we report a molecular mechanism for KSHV-induced IL-10 gene expression. KSHV replication and transcription activator (K-RTA) is a molecular switch for the initiation of expression of viral lytic genes, and we describe, for the first time, that K-RTA significantly activates the promoter of the human IL-10 gene. Of note, mutations involving a basic region of K-RTA reduced the association of K-RTA with the IL-10 promoter. Moreover, the host-cell transcription factors, specificity proteins (SP) 1 and 3, play a pivotal cooperative role in K-RTA–mediated transactivation of the IL-10 promoter. K-RTA can interact with SP1 and SP3 directly in vitro, and electrophoresis mobility shift assays (EMSAs) revealed co-operative interaction involving K-RTA, SP1, and SP3 in binding to the IL-10 promoter. As DNase I footprinting assays indicated that K-RTA did not affect SP3 binding to the IL-10 promoter, SP3 can function to recruit K-RTA to the IL-10 promoter. These findings indicate that K-RTA can directly contribute to IL-10 up-regulation via a functional interplay with the cellular transcription factors SP1 and SP3.