c-Maf suppresses human T-cell leukemia virus type 1 Tax by competing for CREB-binding protein

Latent infection of human T-cell leukemia virus type 1 (HTLV-1) is considered to be preferentially associated with CCR4+ CD4+ T cells. Here we report that c-Maf, one of the critical transcription factors for Th2 differentiation, suppresses the transcriptional activity of HTLV-1 Tax by competing for CREB-binding protein. Notably, c-maf expression is selectively induced in a fraction of CCR4+ CD4+ T cells upon activation. Furthermore, c-Maf significantly decreases Tax-induced HTLV-1 envelope gp46 gene expression from an infectious HTLV-1 molecular clone and tax expression in a cell-free HTLV-1 infection system. Collectively, c-Maf may play a role in latent infection of HTLV-1 in CCR4+ CD4+ T cells by negatively regulating Tax activity. (Cancer Sci 2011; 102: 890–894)