Fig. 4.

HTLV-1 Tax transactivates the CCL1 gene by acting concurrently on AP-1- and CREB-binding sites. The luciferase gene was used to monitor the activity of the CCL1 gene promoter. Four fragments of the 5′-flanking regulatory region of the CCL1 gene were cloned upstream of the luciferase gene, yielding four constructs. These reporter constructs were independently transfected into Jurkat human T-cells with or without the Tax expression plasmid. The results showed that both AP-1- and CREB-binding sites were essential and sufficient for transactivation of the CCL1 gene by HTLV-1 Tax