REGULATION OF GENE-EXPRESSION BY HTLV-I TAX PROTEIN

The human T-cell leukemia virus type I or HTLV-I is the causative agen t of adult T-cell leukemia. A protein encoded by HTLV-I, Tax, activate s viral gene expression and Is essential for transforming T-lymphocyte s. Tax activates HTLV-I gene expression via interactions with the ATF/ CREB proteins and the coactivators CBP/p300 which assemble as a multip rotein complex on regulatory elements known as 21-bp repeats in the HT LV-I LTR. Tax can also activate expression from cellular genes includi ng the interleukin-2 (IL-2) and the IL-2 receptor genes via increases in nuclear levels of NF-kappa B. Tax modulation of gene expression via the ATF/CREB and NF-kappa B pathways is linked to its transforming pr operties. This review discusses the mechanisms by which Tax regulates viral and cellular gene expression. (C) 1998 Academic Press.